Santa Bárbara became the launching place for expeditions into New Mexico by Spanish conquistadors like: Antonio de Espejo, Gaspar Castaño, Antonio Gutiérrez de Umaña, Francisco Leyba de Bonilla, and Vicente de Zaldívar. Several expeditions were led to find a shorter route from Santa Barbara to New Mexico. In April 1598, Juan de Oñate finally found a short route from Santa Barbara to New Mexico which came to be called El Paso del Norte (The Northern Pass). The discovery of El Paso Del Norte was important for the expansion of El Camino Real de Tierra Adentro (The Inner Land Royal Road) to link Spanish settlements in New Mexico to Mexico City; El Camino Real de Tierra Adentro facilitated transport of settlers and supplies to New Mexico.


Hidalgo is hailed as the Father of the Nation even though it was Agustin de Iturbide and not Hidalgo who achieved Mexican Independence in 1821. Shortly after gaining independence, the day to celebrate it varied between September 16, the day of Hidalgo's Grito, and September 27, the day Iturbide rode into Mexico City to end the war. Later, political movements would favor the more liberal Hidalgo over the conservative Iturbide, so that eventually September 16, 1810 became the officially recognized day of Mexican independence. The reason for this is that Hidalgo is considered to be "precursor and creator of the rest of the heroes of the (Mexican War of) Independence." Hidalgo has become an icon for Mexicans who resist tyranny in the country. Diego Rivera painted Hidalgo's image in half a dozen murals. José Clemente Orozco depicted him with a flaming torch of liberty and considered the painting among his best work. David Alfaro Siqueiros was commissioned by San Nicolas University in Morelia to paint a mural for a celebration commemorating the 200th anniversary of Hidalgo's birth. The town of his parish was renamed Dolores Hidalgo in his honor and the state of Hidalgo was created in 1869. Every year on the night of 15–16 September, the president of Mexico re-enacts the Grito from the balcony of the National Palace. This scene is repeated by the heads of cities and towns all over Mexico. The remains of Miguel Hidalgo y Costilla lie in the column of the Angel of Independence in Mexico City. Next to it is a lamp lit to represent the sacrifice of those who gave their lives for Mexican Independence.


On February 8, 1847, Doniphan continued his march with 924 men mostly from Missouri; he accompanied a train of 315 wagons of a large commercial caravan heading to the state capital. Meanwhile, the Mexican forces in the state had time to prepare a defense against the Americans. About 20 miles (32 km) north of the capital where two mountain ranges join from east to west is the only pass into the capital; known as Sacramento Pass, this point is now part of present-day Chihuahua City. The Battle of Sacramento was the most important battle fought in the state of Chihuahua because it was the sole defense for the state capital. The battle ended quickly because of some devastating defensive errors from the Mexican forces and the ingenious strategic moves by the American forces. After their loss at the Battle of Sacramento, the remaining Mexican soldiers retreated south, leaving the city to American occupation. Almost 300 Mexicans were killed in the battle, as well as almost 300 wounded. The Americans also confiscated large amounts of Mexican supplies and took 400 Mexican soldiers prisoners of war. American forces maintained an occupation of the state capital for the rest of the Mexican–American War.


The anti-clerical feeling was widespread, and Durango supported the initial reaction against the government at Mexico. In May 1832, José Urrea, a rising officer, supported the restoration of President Pedraza. On July 20, Governor Elorriaga was reinstated, and Baca along with the legislative minority were brought back to form a new legislature, which met on September 1. Chihuahua showed no desire to imitate the revolutionary movement and Urrea prepared to invade the state. Comandante-general J.J.Calvo threatened to retaliate, and a conflict seemed imminent. The entry of General Santa Anna into Mexico brought calm, as the leaders waited for clarity.


Under threat from the conservative forces, Governor Terrazas was deposed, and the state legislature proclaimed martial law in the state in April 1864 and established Jesús José Casavantes as the new governor. In response, José María Patoni decided to march to Chihuahua with presidential support. Meanwhile, Maximilian von Habsburg, a younger brother of the Emperor of Austria, was proclaimed Emperor Maximilian I of Mexico on April 10, 1864 with the backing of Napoleon III and a group of Mexican conservatives. Before President Benito Juárez was forced to flee, Congress granted him an emergency extension of his presidency, which would go into effect in 1865 when his term expired, and last until 1867. At the same time, the state liberals and conservatives compromised to allow the popular Ángel Trías take the governorship; by this time the French forces had taken control over the central portions of the country and were making preparations to invade the northern states.


The state united behind the Plan of Ayutla and ratified the new constitution in 1855. The state was able to survive through the Reform War with minimal damage due to the large number of liberal political figures. The 1858 conservative movement did not succeed in the state even after the successful military campaign of the conservative Zuloaga with 1,000 men occupied the cities of Chihuahua and Parral. In August 1859, Zuloaga and his forces were defeated by the liberal Orozco and his forces; Orozco soon after deposed the state governor, but had to flee to Durango two months later. In the late 1860s the conservative General Cajen briefly entered the state after his campaign through the state of Jalisco and helped establish conservative politicians and ran out the liberal leaders Jesús González Ortega and José María Patoni. Cajen took possession of the state capital and established himself as governor; he brooked no delay in uniting a large force to combat the liberal forces which he defeated in La Batalla del Gallo. Cajen attained several advantages over the liberals within the state, but soon lost his standing due to a strong resurgence of the liberal forces within the state. The successful liberal leaders José María Patoni of Durango and J.E. Muñoz of Chihuahua quickly strengthened their standing by limiting the political rights of the clergy implementing the presidential decree. The state elected General Luis Terrazas, a liberal leader, as governor; he would continue to fight small battles within the state to suppress conservative uprisings during 1861.


After running imperial military affairs in the states of Coahuila and Durango, General Agustín Enrique Brincourt made preparations to invade the state of Chihuahua. On July 8, 1865 Brincourt crossed the Nazas River in northern Durango, heading toward Chihuahua. On July 22 Brincourt crossed the banks of Río Florido into Ciudad Jiménez; one day later he arrived at Valle de Allende where he sent Colonel Pyot with a garrison to take control of Hidalgo del Parral. Brincourt continued through Santa Rosalia de Camargo and Santa Cruz de Rosales. President Juárez remained in the state capital until August 5, 1865 when he left for El Paso del Norte (present-day Ciudad Juárez) due to evidence that the French were to attack the city. On the same day, the President named General Manuel Ojinaga the new governor and placed him in charge of all the republican forces. Meanwhile, General Villagran surprised the imperial forces in control of Hidalgo de Parral; after a short two-hour battle, Colonel Pyot was defeated and forced to retreat. At the Battle of Parral, the French lost 55 men to the Republican forces. On August 13, 1865, the French forces with an estimated 2,500 men arrived at the outskirts of Chihuahua City, and on August 15, 1865, General Brincourt defeated the republican forces, taking control of the state capital. Brincourt designated Tomás Zuloaga as Prefect of Chihuahua. Fearing the French would continue their campaign to El Paso del Norte, President Juárez relocated to El Carrizal, a secluded place in the mountains near El Paso del Norte, in August 1865, . It would have been easy for the French forces to continue in pursuit of President Juárez across the border, but they feared altercations with American forces. General François Achille Bazaine ordered the French troops to retreat back to the state of Durango after only reaching a point one days travel north of Chihuahua City. General Brincourt asked for 1,000 men to be left behind to help maintain control over the state, but his request was denied. After the death of General Ojinaga, the Republican government declared General Villagran in charge of the fight against the Imperial forces. The French left the state on October 29, 1865. President Juárez returned to Chihuahua City on November 20, 1865 and remained in the city until December 9, 1865 when he returned to El Paso del Norte. Shortly after the president left Chihuahua City, Terrazas was restored as governor of the state on December 11, 1865.


General Aguirre moved to the deserts of the southeastern portion of the state and defeated the French forces in Parral, led by Colonel Cottret. By the middle of 1866, the state of Chihuahua was declared free of enemy control; Parral was the last French stronghold within the state. On June 17, 1866, President Juárez arrived in Chihuahua City and remained in the capital until December 10, 1866. During his two years in the state of Chihuahua, President Juárez passed ordinances regarding the rights of adjudication of property and nationalized the property of the clergy. The distance of the French forces and their allies allowed the Ministry of War, led by General Negrete, to reorganize the state's national guard into the Patriotic Battalion of Chihuahua, which was deployed to fight in the battle of Matamoros, Tamaulipas against the French. After a series of major defeats and an escalating threat from Prussia, France began pulling troops out of Mexico in late 1866. Disillusioned with the liberal political views of Maximilian, the Mexican conservatives abandoned him, and in 1867 the last of the Emperor's forces were defeated. Maximilian was sentenced to death by a military court; despite national and international pleas for amnesty, Juárez refused to commute the sentence. Maximilian was executed by firing squad on June 19, 1867.


The United States Congress declared war on Mexico on May 13, 1846 after only having a few hours to debate. Although President José Mariano Paredes's issuance of a manifesto on May 23 is sometimes considered the declaration of war, Mexico officially declared war by Congress on July 7. After the American invasion of New Mexico, Chihuahua sent 12,000 men led by Colonel Vidal to the border to stop the American military advance into the state. The Mexican forces being impatient to confront the American forces passed beyond El Paso del Norte about 20 miles (32 km) north along the Rio Grande. The first battle that Chihuahua fought was the battle of El Bracito; the Mexican forces consisting of 500 cavalry and 70 infantry confronted a force of 1,100–1,200 Americans on December 25, 1846. The battle ended badly by the Mexican forces that were then forced to retreat back into the state of Chihuahua. By December 27, 1846, the American forces occupied El Paso Del Norte. General Doniphan maintained camp in El Paso Del Norte awaiting supplies and artillery which he received in February 1847.


But the peace in the state did not last long, the elections of 1875 caused new hostilities. Ángel Trías led a new movement against the government in June 1875 and maintained control over the government until September 18, 1875 when Donato Guerra the orchestrator of the Revolution of the North was captured. Donato Guerra was assassinated in a suburb of Chihuahua City where he was incarcerated for conspiring with Ángel Trías. During October 1875 several locations were controlled by rebel forces, but the government finally regained control on November 25, 1875.


Under Governor Miguel Ahumada, the education system in the state was unified and brought under tighter control by the state government, and the metric system was standardized throughout the state to replace the colonial system of weights and measures. On September 16, 1897, the Civilian Hospital of Chihuahua was inaugurated in Chihuahua City and became known among the best in the country. In 1901 the Heroes Theater (Teatro de los Héroes) opened in Chihuahua City. On August 18, 1904, Governor Terrazas was replaced by Governor Enrique C. Creel. From 1907 to 1911, the Creel administration succeeded in advancing the state's legal system, modernizing the mining industry, and raising public education standards. In 1908 the Chihuahuan State Penitentiary was built, and the construction on the first large scale dam project was initiated on the Chuviscar River. During the same time, the streets of Chihuahua City were paved and numerous monuments were built in Chihuahua City and Ciudad Juárez.


Despite the internal stability (known as the paz porfiriana), modernization, and economic growth in Mexico during the Porfiriato from 1876 to 1910, many across the state became deeply dissatisfied with the political system. When Díaz first ran for office, he committed to a strict “No Re-election” policy in which he disqualified himself to serve consecutive terms. Eventually backtracking on many of his initial political positions Díaz became a de facto dictator. Díaz became increasingly unpopular due to brutal suppression of political dissidents by using the Rurales and manipulating the elections to solidify his political machine. The working class was frustrated with the Díaz regime due to the corruption of the political system that had increased the inequality between the rich and poor. The peasants felt disenfranchised by the policies that promoted the unfair distribution of land where 95% of the land was owned by the top 5%.


In response to Madero's letter to action, Pascual Orozco (a wealthy mining baron) and Chihuahua Governor Abraham González formed a powerful military union in the north, taking military control of several northern Mexican cities with other revolutionary leaders, including Pancho Villa. Against Madero's wishes, Orozco and Villa fought for and won Ciudad Juárez. After militias loyal to Madero defeated the Mexican federal army, on May 21, 1911, Madero signed the Treaty of Ciudad Juárez with Díaz. It required that Díaz abdicate his rule and be replaced by Madero. Insisting on a new election, Madero won overwhelmingly in late 1911, and he established a liberal democracy and received support from the United States and popular leaders such as Orozco and Villa. Orozco eventually became disappointed with the Madero's government and led a rebellion against him. He organized his own army, called "Orozquistas"—also called the Colorados ("Red Flaggers")—after Madero refused to agree to social reforms calling for better working hours, pay and conditions. The rural working class, which had supported Madero, now took up arms against him in support of Orozco.


The situation became so tense that war with the United States seemed imminent. On April 22, 1914, on the initiative of Felix A. Sommerfeld and Sherburne Hopkins, Pancho Villa traveled to Juárez to calm fears along the border and asked President Wilson's emissary George Carothers to tell "Señor Wilson" that he had no problems with the American occupation of Veracruz. Carothers wrote to Secretary William Jennings Bryan: "As far as he was concerned we could keep Vera Cruz [sic] and hold it so tight that not even water could get in to Huerta and . . . he could not feel any resentment". Whether trying to please the U.S. government or through the diplomatic efforts of Sommerfeld and Carothers, or maybe as a result of both, Villa stepped out from under Carranza’s stated foreign policy.


The state of Chihuahua is the largest state in the country and is known as El Estado Grande (The Big State); it accounts for 12.6% of the land of Mexico. The area is landlocked by the states of Sonora to the west, Sinaloa to the south-west, Durango to the south, and Coahuila to the east, and by the U.S. states of Texas to the northeast and New Mexico to the north. The state is made up of three geologic regions: Mountains, Plains-Valleys, and Desert, which occur in large bands from west to east. Because of the different geologic regions there are contrasting climates and ecosystems.


The climate in the state depends mainly in the elevation of the terrain. According to Köppen climate classification the state has five major climate zones. The Sierra Madre Occidental dominates the western part of the state; there are two main climates in this area: Subtropical Highland (Cfb) and Humid Subtropical (Cwa). There are some microclimates in the state due to the varying topology mostly found in the western side of the state. The two best known microclimates are: Tropical savanna climate (Aw) in deep canyons located in the extreme southern part of the state; Continental Mediterranean climate (Dsb) in the extremely high elevations of the Sierra Madre Occidental. Satellite image to the right shows the vegetation is much greener in the west because of the cooler temperatures and larger amounts of precipitation as compared to the rest of the state.


The Chihuahuan Desert is home to a diverse ecosystem which is home to a large variety of mammals. The most common mammals in the desert include: Desert cottontail Sylvilagus audubonii, black-tailed jackrabbit Lepus californicus, hooded skunk Mephitis macroura, cactus mouse Peromyscus eremicus, swift fox Vulpes velox, white-throated woodrat Neotoma albigula, pallid bat Antrozous pallidus, and coyote Canis latrans. The most observed reptiles in the desert include: Mohave rattlesnake Crotalus scutulatus, twin-spotted rattlesnake Crotalus pricei, prairie rattlesnake Crotalus viridis, ridge-nosed rattlesnake Crotalus willardi, whip snake Masticophis flagellum, New Mexico whiptail Cnemidophorus neomexicanus, and red-spotted toad Bufo punctatus.


Villa and Carranza had different political goals causing Villa to become an enemy of Carranza. After Carranza took control in 1914, Villa and other revolutionaries who opposed him met at what was called the Convention of Aguascalientes. The convention deposed Carranza in favor of Eulalio Gutiérrez. In the winter of 1914 Villa's and Zapata's troops entered and occupied Mexico City. Villa was forced from the city in early 1915 and attacked the forces of Gen. Obregón at the Battle of Celaya and was badly defeated in the bloodiest battle of the revolution, with thousands dead. With the defeat of Villa, Carranza seized power. A short time later the United States recognized Carranza as president of Mexico. Even though Villa's forces were badly depleted by his loss at Celaya, he continued his fight against the Carranza government. Finally, in 1920, Obregón—who had defeated him at Celaya—finally reached an agreement with Villa end his rebellion.


The plains at the foot of the Sierra Madre Occidental is an elongated mesa known as Altiplanicie Mexicana that exhibits a steppe climate and serves as a transition zone from the mountain climate in the western part of the state to the desert climate in the eastern side of the state. The steppe zone accounts for a third of the state's area, and it experiences pronounced dry and wet seasons. The pronounced rainy season in the steppe is usually observed in the months of July, August, and September. The steppe also encounters extreme temperatures that often reach over 100 °F in the summer and drop below 32 °F in the winter. The steppe zone is an important agriculture zone due to an extensive development of canals exploiting several rivers that flow down from the mountains. The steppe zone is the most populated area of the state.


The state has a great diversity due to the large number of microclimates found and dramatic varying terrain. The flora throughout the Sierra Madre Occidental mountain range varies with elevation. Pine (Pinus) and oak (Quercus) species are usually found at an elevation of 2,000 m (6,560 ft) above sea level. The most common species of flora found in the mountains are: Pinus, Quercus, Abies, Ficus, Vachellia, Ipomoea, Acacia, Lysiloma, Bursera, Vitex, Tabebuia, Sideroxylon, Cordia, Fouquieria, Pithecellobium. The state is home to one of the largest variation species of the genus Pinus in the world. The lower elevations have a steppe vegetation with a variety of grasses and small bushes. Several species of Juniperus dot the steppe and the transition zone.


The state has one city with a population exceeding one million: Ciudad Juárez. Ciudad Juárez is ranked eighth most populous city in the country and Chihuahua City was ranked 16th most populous in Mexico. Chihuahua (along with Baja California) is the only state in Mexico to have two cities ranked in the top 20 most populated. El Paso and Ciudad Juárez comprise one of the largest binational metropolitan areas in the world with a combined population of 2.4 million. In fact, Ciudad Juárez is one of the fastest growing cities in the world in spite of the fact that it is "the most violent zone in the world outside of declared war zones". For instance, a few years ago the Federal Reserve Bank of Dallas published that in Ciudad Juárez "the average annual growth over the 10-year period 1990–2000 was 5.3 percent. Juárez experienced much higher population growth than the state of Chihuahua and than Mexico as a whole". Chihuahua City has one of the highest literacy rates in the country at 98%; 35% of the population is aged 14 or below, 60% 15-65, and 5% over 65. The growth rate is 2.4%. The 76.5% of the population of the state of Chihuahua live in cities which makes the state one of the most urbanized in Mexico.


The French forces tried to subdue and capture the liberal government based in Saltillo. On September 21, 1864, José María Patoni and Jesús González Ortega lost against the French forces at the Battle of Estanzuelas; the supreme government led by President Juárez was forced to evacuate the city of Saltillo and relocate to Chihuahua. Juárez stopped in Ciudad Jiménez, Valle de Allende, and Hidalgo de Parral, in turn. He decreed Parral the capital of Mexico from October 2–5, 1864. Perceiving the threat from the advancing French forces, the president continued his evacuation through Santa Rosalía de Camargo, Santa Cruz de Rosales, and finally Chihuahua, Chihuahua. On October 12, 1864, the people of the state gave President Juárez an overwhelmingly supportive reception, led by Governor Ángel Trías. On October 15, 1864 the city of Chihuahua was declared the temporary capital of Mexico.


President Benito Juárez was re-elected in the general election of 1867 in which he received strong liberal support, especially in Chihuahua. Luis Terrazas was confirmed by the people of Chihuahua to be governor of the state. But soon after the election, President Juárez had another crisis on his hands; the Juárez administration was suspected to be involved in the assassination of the military chief José María Patoni executed by General Canto in August 1868. General Canto turned himself over to Donato Guerra. Canto was sentenced to death, but later his sentence changed to 10 years imprisonment. The sense of injustice gave rise to a new rebellion in 1869 that threatened the federal government. In response, the Juárez administration took drastic measures by temporarily suspending constitutional rights, but the governor of Chihuahua did not support this action. Hostilities continued to increase especially after the election of 1871 which was perceived to be fraudulent. A new popular leader arose among the rebels, Porfirio Díaz. The federal government was successful in quelling rebellions in Durango an Chihuahua. On July 18, 1872, President Juárez died from a heart attack; soon after, many of his supporters ceased the fighting. Peace returned to Chihuahua and the new government was led by Governor Antonio Ochoa (formerly a co-owner of the Batopilas silver mines) in 1873 after Luis Terrazas finished his term in 1872.


The Díaz administration made political decisions and took legal measures that allowed the elite throughout Mexico to concentrate the nation's wealth by favoring monopolies. During this time, two-fifths of the state's territory was divided among 17 rich families which owned practically all of the arable land in Chihuahua. The state economy grew at a rapid pace during the Porfiriato; the economy in Chihuahua was dominated by agriculture and mining. The Díaz administration helped Governor Luis Terrazas by funding the Municipal Public Library in Chihuahua City and passing a federal initiative for the construction of the railroad from Chihuahua City to Ciudad Júarez. By 1881, the Central Mexican Railroad was completed which connected Mexico City to Ciudad Juárez. In 1883 telephone lines were installed throughout the state, allowing communication between Chihuahua City and Aldama. By 1888 the telephone services were extended from the capital to the cites of Julimes, Meoqui, and Hidalgo del Parral; the telecommunication network in the state covered an estimated 3,500 kilometers. The need of laborers to construct the extensive infrastructure projects resulted in a significant Asian immigration, mostly from China. Asian immigrants soon become integral to the state economy by opening restaurants, small grocery stores, and hotels. By the end of the Terrazas term, the state experienced an increase in commerce, mining, and banking. When the banks were nationalized, Chihuahua became the most important banking state in Mexico.


The end of the Porfiriato came in 1910 with the beginning of the Mexican Revolution. Díaz had stated that Mexico was ready for democracy and he would step down to allow other candidates to compete for the presidency, but Díaz decided to run again in 1910 for the last time against Francisco I. Madero. During the campaign Díaz incarcerated Madero on election day in 1910. Díaz was announced the winner of the election by a landslide, triggering the revolution. Madero supporter Toribio Ortega took up arms with a group of followers at Cuchillo Parado, Chihuahua on November 10, 1910.


The uneasy alliance of Carranza, Obregón, Villa, and Zapata eventually led the rebels to victory. The fight against Huerta formally ended on August 15, 1914, when Álvaro Obregón signed a number of treaties in Teoloyucan in which the last of Huerta's forces surrendered to him and recognized the constitutional government. On August 20, 1914, Carranza made a triumphal entry into Mexico City. Carranza (supported by Obregón) was now the strongest candidate to fill the power vacuum and set himself up as head of the new government. This government successfully printed money, passed laws, etc.


The main mountain range in the state is the Sierra Madre Occidental reaching a maximum altitude of 10,826 ft (3,300 m) known as Cerro Mohinora. Mountains account for one third of the state's surface area which include large coniferous forests. The climate in the mountainous regions varies Chihuahua has more forests than any other state in Mexico making the area a bountiful source of wood; the mountainous areas are rich in minerals important to Mexico's mining industry. Precipitation and temperature in the mountainous areas depends on the elevation. Between the months of November and March snow storms are possible in the lower elevations and are frequent in the higher elevations. There are several watersheds located in the Sierra Madre Occidental all of the water that flows through the state; most of the rivers finally empty into the Río Grande. Temperatures in some canyons in the state reach over 100 °F in the summer while the same areas rarely drop below 32 °F in the winter. Microclimates found in the heart of the Sierra Madre Occidental in the state could be considered tropical, and wild tropical plants have been found in some canyons. La Barranca del Cobre, or Copper Canyon, a spectacular canyon system larger and deeper than the Grand Canyon; the canyon also contains Mexico's two tallest waterfalls: Basaseachic Falls and Piedra Volada. There are two national parks found in the mountainous area of the state: Cumbres de Majalca National Park and Basaseachic Falls National Park.


In the far eastern part of the state the Chihuahuan Desert dominates due to low precipitation and extremely high temperatures; some areas of the eastern part of the state are so dry no vegetation is found like the Sand Dunes of Samalayuca. There are two distinctive climate zones found in the eastern part of the state: Hot Desert (BWh) and Cool Desert (BWk) which are differentiated by average annual temperature due to differences in elevation. There is a transition zone in the middle of the state between the two extremely different climates from the east and west; this zone is the Steppe characterized by a compromise between juxtaposed climate zones.


The state is also a host to a large population of birds which include endemic species and migratory species: greater roadrunner Geococcyx californianus, cactus wren Campylorhynchus brunneicapillus, Mexican jay Aphelocoma ultramarina, Steller's jay Cyanocitta stelleri, acorn woodpecker Melanerpes formicivorus, canyon towhee Pipilo fuscus, mourning dove Zenaida macroura, broad-billed hummingbird Cynanthus latirostris, Montezuma quail Cyrtonyx montezumae, mountain trogon Trogon mexicanus, turkey vulture Cathartes aura, and golden eagle Aquila chrysaetos. Trogon mexicanus is an endemic species found in the mountains in Mexico; it is considered an endangered species[citation needed] and has symbolic significance to Mexicans.


During the Mexican Revolution, Álvaro Obregón invited a group of Canadian German-speaking Mennonites to resettle in Mexico. By the late 1920s, some 7,000 had immigrated to Chihuahua State and Durango State, almost all from Canada, only a few from the U.S. and Russia. Today, Mexico accounts for about 42% of all Mennonites in Latin America. Mennonites in the country stand out because of their light skin, hair, and eyes. They are a largely insular community that speaks a form of German and wear traditional clothing. They own their own businesses in various communities in Chihuahua, and account for about half of the state's farm economy, excelling in cheese production.


Agriculture is a relatively small component of the state's economy and varies greatly due to the varying climate across the state. The state ranked first in Mexico for the production of the following crops: oats, chile verde, cotton, apples, pecans, and membrillo. The state has an important dairy industry with large milk processors throughout the state. Delicias is home to Alpura, the second-largest dairy company in Mexico. The state has a large logging industry ranking second in oak and third in pine in Mexico. The mining industry is a small but continues to produce large amounts of minerals. The state ranked first place in the country for the production of lead with 53,169 metric tons. Chihuahua ranked second in Mexico for zinc at 150,211 metric tons, silver at 580,271 kg, and gold at 15,221.8 kg.


Nueva Vizcaya (New Biscay) was the first province of northern New Spain to be explored and settled by the Spanish. Around 1528, a group of Spaniard explorers, led by Álvar Núñez Cabeza de Vaca, first entered the actual territory of what is now Chihuahua. The conquest of the territory lasted nearly one century, and encountered fierce resistance from the Conchos tribe, but the desire of the Spanish Crown to transform the region into a bustling mining center led to a strong strategy to control the area.


Hidalgo was turned over to the Bishop of Durango, Francisco Gabriel de Olivares, for an official defrocking and excommunication on July 27, 1811. He was then found guilty of treason by a military court and executed by firing squad on July 30 at 7 in the morning. Before his execution, he thanked his jailers, Private Soldiers Ortega and Melchor, in letters for their humane treatment. At his execution, Hidalgo placed his right hand over his heart to show the riflemen where they should aim. He also refused the use of a blindfold. His body, along with the bodies of Allende, Aldama and José Mariano Jiménez were decapitated, and the heads were put on display on the four corners of the Alhóndiga de Granaditas in Guanajuato. The heads remained there for ten years until the end of the Mexican War of Independence to serve as a warning to other insurgents. Hidalgo's headless body was first displayed outside the prison but then buried in the Church of St Francis in Chihuahua. Those remains would later be transferred in 1824 to Mexico City.


Because of the general instability of the federal government during 1828, the installation of the new legislature did not take place until the middle of the following year. It was quickly dissolved by Governor Santiago de Baca Ortiz, who replaced it with a more pronounced Yorkino type. When Guerrero's liberal administration was overthrown in December, Gaspar de Ochoa aligned with Anastasio Bustamante, and in February 1830, organized an opposition group that arrested the new governor, F. Elorriaga, along with other prominent Yorkinos. He then summoned the legislature, which had been dissolved by Baca. The civil and military authorities were now headed by J. A. Pescador and Simón Ochoa.


Comandante general Simón Elías González, was nominated governor and military command was given to Colonel J.J. Calvo, whose firmness had earned well-merited praise. The state was in the midst of a war with the Apaches, which became the focus of all their energy and resources. After a review of the situation, Simón Elías González declared that the interests of the territory would be best served by uniting the civil and military power, at least while the campaign lasted. He resigned under opposition, but was renominated in 1837.


During the American occupation of the state, the number of Indian attacks was drastically reduced, but in 1848 the attacks resumed to such a degree that the Mexican officials had no choice but to resume military projects to protect Mexican settlements in the state. Through the next three decades the state faced constant attacks from indigenous on Mexican settlements. After the occupation the people of the state were worried about the potential attack from the hostile indigenous tribes north of the Rio Grande; as a result a decree on July 19, 1848, the state established 18 military colonies along the Rio Grande. The new military colonies were to replace the presidios as population centers to prevent future invasions by indigenous tribes; these policies remained prominent in the state until 1883. Eventually the state replaced the old state security with a state policy to form militias organized with every Mexican in the state capable to serve between the ages of 18 and 55 to fulfill the mandate of having six men defending for every 1000 residents.


The liberal political forces maintained strong control over the state government until shortly after the French Intervention which turned the tables in favor to the conservative forces once again. The intervention had serious repercussions for the state of Chihuahua. President Juárez, in an effort to organize a strong defense against the French, decreed a list of national guard units that every state had to contribute to the Ministry of War and the Navy; Chihuahua was responsible for inducting 2,000 men. Regaining power, Governor Luis Terrazas assigned the First Battalion of Chihuahua for integration into the national army led by General Jesús González Ortega; the battalion was deployed to Puebla. After the defeat of the army in Puebla, the Juárez administration was forced to abandon Mexico City; the president retreated further north seeking refuge in the state of Chihuahua.


President Juárez once again based his government in the state of Chihuahua and it served as the center for the resistance against the French invasion throughout Mexico. On March 25, 1866, a battle ensued in the Plaza de Armas in the center of Chihuahua City between the French imperial forces that were guarding the plaza and the Republican forces led by General Terrazas. Being completely caught off guard, the French imperial forces sought refuge by bunkering themselves in the Cathedral of the Holy Cross, Our Lady of Regla, and St Fancis of Assisi and made it almost impossible to penetrate their defenses. General Terrazas then decided to fire a heavy artillery barrage with 8 kg cannonballs. The first cannon fired hit a bell in the tower of the church, instantly breaking it in half; soon after, 200 men of the imperial army forces surrendered. The republican forces had recovered control over the state capital. The bell in the church was declared a historical monument and can be seen today in the Cathedral. By April 1866, the state government had established a vital trading route from Chihuahua City to San Antonio, Texas; the government began to replenish their supplies and reinforce their fight against the Imperial forces.


The officials in Mexico City reduced the price of corn from six cents to two cents a pound. The northern portion of the state continued to decline economically which led to another revolt led by G. Casavantes in August 1879; Governor Trías was accused of misappropriation of funds and inefficient administration of the state. Casavantes took the state capital and occupied it briefly; he was also successful in forcing Governor Trías to exile. Shortly afterwards, the federal government sent an entourage led by Treviño; Casavantes was immediately ordered to resign his position. Casavantes declared political victory as he was able to publicly accuse and depose Governor Trías. At the same time the states of Durango and Coahuila had a military confrontation over territorial claims and water rights; this altercation between the state required additional federal troops to stabilize the area. Later a dispute ensued again among the states of Coahuila, Durango, and Chihuahua over the mountain range area known as Sierra Mojada, when large deposits of gold ore was discovered. The state of Chihuahua officially submitted a declaration of protest in May 1880 that shortly after was amicably settled. Despite the difficulties at the beginning, Díaz was able to secure and stabilize the state, which earned the confidence and support of the people.


A handful of families owned large estates (known as haciendas) and controlled the greater part of the land across the state while the vast majority of Chihuahuans were landless. The state economy was largely defined by ranching and mining. At the expense of the working class, the Díaz administration promoted economic growth by encouraging investment from foreign companies from the United Kingdom, France, Imperial Germany and the United States. The proletariat was often exploited, and found no legal protection or political recourse to redress injustices.


On March 26, 1913, Venustiano Carranza issued the Plan de Guadalupe, which refused to recognize Huerta as president and called for war between the two factions. Soon after the assassination of President Madero, Carranza returned to Mexico to fight Huerta, but with only a handful of comrades. However, by 1913 his forces had swelled into an army of thousands, called the División del Norte (Northern Division). Villa and his army, along with Emiliano Zapata and Álvaro Obregón, united with Carranza to fight against Huerta. In March 1914 Carranza traveled to Ciudad Juárez, which served as rebellion's capital for the remainder of the struggle with Huerta. In April 1914 U.S. opposition to Huerta had reached its peak, blockading the regime's ability to resupply from abroad. Carranza trying to keep his nationalistic credentials threatened war with the United States. In his spontaneous response to U.S. President Woodrow Wilson Carranza asked "that the president withdraw American troops from Mexico.”


The desert zone also accounts for about a third of the state's surface area. The Chihuahuan Desert is an international biome that also extends into the neighboring Mexican state of Coahuila and into the U.S. states of Texas and New Mexico. The desert zone is mainly of flat topography with some small mountain ranges that run north to south. The desert in the state varies slightly with a small variant in climate. The lower elevations of the desert zone are found in the north along the Rio Grande which experience hotter temperatures in the summer and winter while the southern portion of the desert zone experiences cooler temperatures due to its higher elevation. The Samalayuca dunes cover an area of about 150 km2; it is an impressive site of the Chihuahuan Desert and is a protected area by the state due to unique species of plants and animals.


The fauna in the state is just as diverse as the flora and varies greatly due to the large contrast in climates. In the mountain zone of the state the most observed mammals are: Mexican fox squirrel (Sciurus nayaritensis), antelope jackrabbit (Lepus alleni), raccoon (Procyon lotor), hooded skunk (Mephitis macroura), wild boar (Sus scrofa), collared peccary (Pecari tajacu), white-tailed deer (Odocoileus virginianus), mule deer Odocoileus hemionus, American bison Bison bison, cougar (Puma concolor), eastern cottontail Sylvilagus floridanus, North American porcupine Erethizon dorsatum, bobcat Lynx rufus, Mexican wolf Canis lupus baileyi, and coyote Canis latrans. American black bear Ursus americanus is also found but in very small numbers. The Mexican wolf, once abundant, has been extirpated. The main cause of degradation has been grazing. Although there are many reptilian species in the mountains the most observed species include: Northern Mexican pine snake, Pituophis deppei jani, Texas horned lizard (Phrynosoma cornutum), rock rattlesnake (Crotalus lepidus), black-tailed rattlesnake (Crotalus molossus), and plateau tiger salamander Ambystoma velasci, one of possibly many amphibians to be found in the mountains.


The last census in Mexico that asked for an individual's race, which was taken in 1921, indicated that 50.09% of the population identified as Mestizo (mixed Amerindian and European descent). The second-largest group was whites at 36.33% of the population. The third-largest group was the "pure indigenous" population, constituting 12.76% of the population. The remaining 0.82% of the population of Chihuahua was considered "other", i.e., neither Mestizo, indigenous, nor white. The most important indigenous tribes of the state of Chihuahua are:


During the 1990s after NAFTA was signed, industrial development grew rapidly with foreign investment. Large factories known as maquiladoras were built to export manufactured goods to the United States and Canada. Today, most of the maquiladoras produce electronics, automobile, and aerospace components. There are more than 406 companies operating under the federal IMMEX or Prosec program in Chihuahua. The large portion of the manufacturing sector of the state is 425 factories divided into 25 industrial parks accounting for 12.47% of the maquiladoras in Mexico, which employ 294,026 people in the state. While export-driven manufacturing is one of the most important components of the state's economy, the industrial sector is quite diverse and can be broken down into several sectors, which are: electronics, agro-industrial, wood base manufacturing, mineral, and biotech. Similar to the rest of the country, small businesses continue to be the foundation of the state’s economy. Small business employs the largest portion of the population.[citation needed]


Shias believe that Imamah is of the Principles of Faith (Usul al-Din).As the verse 4:165 of quran expresses the necessity to the appointment of the prophets; so after the demise of the prophet who will play the role of the prophet; till the people have not any plea against Allah.So the same logic that necessitated the assignment of prophets also is applied for Imamah.That is Allah Must assign someone similar to prophet in his attributes and Ismah as his successor to guide the people without any deviation in religion. They refer to the verse (...This day I have perfected for you your religion and completed My favor upon you and have approved for you Islam as religion...) 5:3 of Quran which was revealed to the prophet when he appointed Ali as his successor at the day of Ghadir Khumm.


Imamah (Arabic: إمامة) is the Shia Islam doctrine (belief) of religious, spiritual and political leadership of the Ummah. The Shia believe that the Imams are the true Caliphs or rightful successors of Muhammad, and further that Imams are possessed of divine knowledge and authority (Ismah) as well as being part of the Ahl al-Bayt, the family of Muhammad. These Imams have the role of providing commentary and interpretation of the Quran as well as guidance to their tariqa followers as is the case of the living Imams of the Nizari Ismaili tariqah.


Within Shia Islam (Shiism), the various sects came into being because they differed over their Imams' successions, just as the Shia - Sunni separation within Islam itself had come into being from the dispute that had arisen over the succession to Muhammad. Each succession dispute brought forth a different tariqah (literal meaning 'path'; extended meaning 'sect') within Shia Islam. Each Shia tariqah followed its own particular Imam's dynasty, thus resulting in different numbers of Imams for each particular Shia tariqah. When the dynastic line of the separating successor Imam ended with no heir to succeed him, then either he (the last Imam) or his unborn successor was believed to have gone into concealment, that is, The Occultation.


It is forbidden for the Divine Leader not to be from the family of Muhammad.[citation needed] According to Ali al-Ridha, since it is obligatory to obey him, there should be a sign to clearly indicate the Divine Leader. That sign is his well-known ties of kinship with Muhammad and his clear appointment so that the people could distinguish him from others, and be clearly guided toward him. Otherwise others are nobler than Muhammad's offspring and they are to be followed and obeyed; and the offspring of Muhammad are obedient and subject to the offspring of Muhammad’s enemies such as Abi Jahl or Ibn Abi Ma’eet.[original research?] However, Muhammad is much nobler than others to be in charge and to be obeyed. Moreover, once the prophethood of Muhammad is testified they would obey him, no one would hesitate to follow his offspring and this would not be hard for anyone. While to follow the offspring of the corrupted families is difficult.[original research?] And that is maybe why the basic characteristic of Muhammad and other prophets was their nobility.[original research?] For none of them, it is said, were originated from a disgraced family.[citation needed] It is believed that all Muhammad's ancestors up to Adam were true Muslims. [a][citation needed] Jesus was also from a pious family, as it is mentioned in Quran that after his birth, people said to Mary: O sister of Aaron, your father was not a man of evil, nor was your mother unchaste."[b][improper synthesis?]


The word "Imām" denotes a person who stands or walks "in front". For Sunni Islam, the word is commonly used to mean a person who leads the course of prayer in the mosque. It also means the head of a madhhab ("school of thought"). However, from the Shia point of view this is merely the basic understanding of the word in the Arabic language and, for its proper religious usage, the word "Imam" is applicable only to those members of the house of Muhammad designated as infallible by the preceding Imam.


Although all these different Shia tariqahs belong to the Shia group (as opposed to the Sunni group) in Islam, there are major doctrinal differences between the main Shia tariqahs. After that there is the complete doctrinal break between all the different Shia tariqahs whose last Imams have gone into Occultation and the Shia Nizari Ismailis who deny the very concept of Occultation. The Shia Nizari Ismailis by definition have to have a present and living Imam until the end of time.[citation needed] Thus if any living Nizari Ismaili Imam fails to leave behind a successor after him then the Nizari Ismailism’s cardinal principle would be broken and it’s very raison d'être would come to an end.


According to Ismā‘īlīsm, Allah has sent "seven" great prophets known as “Nātıq” (Spoken) in order to disseminate and improve his Dīn of Islam. All of these great prophets has also one assistant known as “Sāmad (Silent) Imām”. At the end of each seven “Sāmad” silsila, one great “Nātıq” (Spoken) has ben sent in order to reimprove the Dīn of Islam. After Adam and his son Seth, and after six “Nātıq” (Spoken) – “Sāmad” (Silent) silsila (Noah–Shem), (Abraham–Ishmael), (Moses–Aaron), (Jesus–Simeon), (Muhammad bin ʿAbd Allāh–Ali ibn Abu Tālib); the silsila of “Nātıqs and Sāmads have been completed with (Muhammad bin Ismā‘īl as-ṣaghīr (Maymûn’ûl-Qaddāh)–ʿAbd Allāh Ibn-i Maymûn and his sons).


The Shia tariqah with a majority of adherents are the Twelvers who are commonly known as the "Shia". After that come the Nizari Ismailis commonly known as the Ismailis; and then come the Mustalian Ismailis commonly known as the "Bohras" with further schisms within their Bohri tariqah. The Druze tariqah (very small in number today) initially were of the Fatimid Ismailis and separated from them (the Fatimid Ismailis) after the death of the Fatimid Imam and Caliph Hakim Bi Amrillah. The Shia Sevener tariqah no longer exists. Another small tariqah is the Zaidi Shias, also known as the Fivers and who do not believe in The Occultation of their last Imam.


During the Minor Occultation (Ghaybat al-Sughrá), it is believed that al-Mahdi maintained contact with his followers via deputies (Arab. an-nuwāb al-arbaʻa or "the Four Leaders"). They represented him and acted as agents between him and his followers. Whenever the believers faced a problem, they would write their concerns and send them to his deputy. The deputy would ascertain his verdict, endorse it with his seal and signature and return it to the relevant parties. The deputies also collected zakat and khums on his behalf.


The Ismailis differ from Twelvers because they had living imams for centuries after the last Twelver Imam went into concealment. They followed Isma'il ibn Jafar, elder brother of Musa al-Kadhim, as the rightful Imam after his father Ja'far al-Sadiq. The Ismailis believe that whether Imam Ismail did or did not die before Imam Ja'far, he had passed on the mantle of the imamate to his son Muḥammad ibn Ismail as the next imam. Thus, their line of imams is as follows (the years of their individual imamats during the Common Era are given in brackets):


The line of imams of the Mustali Ismaili Shia Muslims (also known as the Bohras/Dawoodi Bohra) continued up to Aamir ibn Mustali. After his death, they believe their 21st Imam Taiyab abi al-Qasim went into a Dawr-e-Satr (period of concealment) that continues to this day. In the absence of an imam they are led by a Dai-al-Mutlaq (absolute missionary) who manages the affairs of the Imam-in-Concealment until re-emergence of the Imam from concealment. Dawoodi Bohra's present 53rd Da'i al-Mutlaq is His Holiness Syedna Mufaddal Saifuddin (TUS) who succeeded his predessor the 52nd Da'i al-Mutlaq His Holiness Syedna Mohammed Burhanuddin (RA). Furthermore, there has been a split in the Dawoodi Bohra sect which has led to the formation of Qutbi Bohra sect which was formed and led by Khuzaima Qutbuddin.


All Muslims believe that Muhammad had said: "To whomsoever I am Mawla, Ali is his Mawla." This hadith has been narrated in different ways by many different sources in no less than 45 hadith books[citation needed] of both Sunni and Shia collections. This hadith has also been narrated by the collector of hadiths, al-Tirmidhi, 3713;[citation needed] as well as Ibn Maajah, 121;[citation needed] etc. The major point of conflict between the Sunni and the Shia is in the interpretation of the word 'Mawla'. For the Shia the word means 'Lord and Master' and has the same elevated significance as when the term had been used to address Muhammad himself during his lifetime. Thus, when Muhammad actually (by speech) and physically (by way of having his closest companions including Abu Bakr, Umar and Uthman [the three future Caliphs who had preceded Ali as Caliph] publicly accept Ali as their Lord and Master by taking Ali's hand in both of theirs as token of their allegiance to Ali) transferred this title and manner of addressing Ali as the Mawla for all Muslims at Ghadiri Khum Oasis just a few months before his death, the people that came to look upon Ali as Muhammad's immediate successor even before Muhamamd's death came to be known as the Shia. However, for the Sunnis the word simply means the 'beloved' or the 'revered' and has no other significance at all.


By the verse Quran, 2:124, Shias believe that Imamah is a divine position always Imamah is accompanied by the word guidance, of course a guidance by God's Command.A kind of guidance which brings humanity to the goal. Regarding 17:71, no age can be without an Imam. So, according to the upper verse 1.Imamah is a position which is appointed by God and must be specified by Him 2.Imam is protected by a divine protection and no one exceles him in nobility 3. No age can be without an Imam and finally Imam knows everything which is needed for human being to get to the truth and goal.


According to the majority of Shī'a, namely the Twelvers (Ithnā'ashariyya), the following is a listing of the rightful successors to Muḥammad. Each Imam was the son of the previous Imam except for Hussayn ibn 'Alī, who was the brother of Hassan ibn 'Alī.The belief in this succession to Muḥammad stems from various Quranic verses which include: 75:36, 13:7, 35:24, 2:30, 2:124, 36:26, 7:142, 42:23.[citation needed] They support their discussion by citing Genesis 17:19–20 and Sunni hadith:Sahih Muslim, Hadith number 4478, English translation by Abdul Hamid Siddiqui.[original research?]


Pitch is an auditory sensation in which a listener assigns musical tones to relative positions on a musical scale based primarily on their perception of the frequency of vibration. Pitch is closely related to frequency, but the two are not equivalent. Frequency is an objective, scientific attribute that can be measured. Pitch is each person's subjective perception of a sound, which cannot be directly measured. However, this does not necessarily mean that most people won't agree on which notes are higher and lower.


This creates a linear pitch space in which octaves have size 12, semitones (the distance between adjacent keys on the piano keyboard) have size 1, and A440 is assigned the number 69. (See Frequencies of notes.) Distance in this space corresponds to musical intervals as understood by musicians. An equal-tempered semitone is subdivided into 100 cents. The system is flexible enough to include "microtones" not found on standard piano keyboards. For example, the pitch halfway between C (60) and C♯ (61) can be labeled 60.5.


The relative pitches of individual notes in a scale may be determined by one of a number of tuning systems. In the west, the twelve-note chromatic scale is the most common method of organization, with equal temperament now the most widely used method of tuning that scale. In it, the pitch ratio between any two successive notes of the scale is exactly the twelfth root of two (or about 1.05946). In well-tempered systems (as used in the time of Johann Sebastian Bach, for example), different methods of musical tuning were used. Almost all of these systems have one interval in common, the octave, where the pitch of one note is double the frequency of another. For example, if the A above middle C is 440 Hz, the A an octave above that is 880 Hz (info).


According to the American National Standards Institute, pitch is the auditory attribute of sound according to which sounds can be ordered on a scale from low to high. Since pitch is such a close proxy for frequency, it is almost entirely determined by how quickly the sound wave is making the air vibrate and has almost nothing to do with the intensity, or amplitude, of the wave. That is, "high" pitch means very rapid oscillation, and "low" pitch corresponds to slower oscillation. Despite that, the idiom relating vertical height to sound pitch is shared by most languages. At least in English, it is just one of many deep conceptual metaphors that involve up/down. The exact etymological history of the musical sense of high and low pitch is still unclear. There is evidence that humans do actually perceive that the source of a sound is slightly higher or lower in vertical space when the sound frequency is increased or decreased.


A sound generated on any instrument produces many modes of vibration that occur simultaneously. A listener hears numerous frequencies at once. The vibration with the lowest frequency is called the fundamental frequency; the other frequencies are overtones. Harmonics are an important class of overtones with frequencies that are integer multiples of the fundamental. Whether or not the higher frequencies are integer multiples, they are collectively called the partials, referring to the different parts that make up the total spectrum.


The pitch of complex tones can be ambiguous, meaning that two or more different pitches can be perceived, depending upon the observer. When the actual fundamental frequency can be precisely determined through physical measurement, it may differ from the perceived pitch because of overtones, also known as upper partials, harmonic or otherwise. A complex tone composed of two sine waves of 1000 and 1200 Hz may sometimes be heard as up to three pitches: two spectral pitches at 1000 and 1200 Hz, derived from the physical frequencies of the pure tones, and the combination tone at 200 Hz, corresponding to the repetition rate of the waveform. In a situation like this, the percept at 200 Hz is commonly referred to as the missing fundamental, which is often the greatest common divisor of the frequencies present.


The just-noticeable difference (jnd) (the threshold at which a change is perceived) depends on the tone's frequency content. Below 500 Hz, the jnd is about 3 Hz for sine waves, and 1 Hz for complex tones; above 1000 Hz, the jnd for sine waves is about 0.6% (about 10 cents). The jnd is typically tested by playing two tones in quick succession with the listener asked if there was a difference in their pitches. The jnd becomes smaller if the two tones are played simultaneously as the listener is then able to discern beat frequencies. The total number of perceptible pitch steps in the range of human hearing is about 1,400; the total number of notes in the equal-tempered scale, from 16 to 16,000 Hz, is 120.


It is still possible for two sounds of indefinite pitch to clearly be higher or lower than one another. For instance, a snare drum sounds higher pitched than a bass drum though both have indefinite pitch, because its sound contains higher frequencies. In other words, it is possible and often easy to roughly discern the relative pitches of two sounds of indefinite pitch, but sounds of indefinite pitch do not neatly correspond to any specific pitch. A special type of pitch often occurs in free nature when sound reaches the ear of an observer directly from the source, and also after reflecting off a sound-reflecting surface. This phenomenon is called repetition pitch, because the addition of a true repetition of the original sound to itself is the basic prerequisite.


For example, one might refer to the A above middle C as a', A4, or 440 Hz. In standard Western equal temperament, the notion of pitch is insensitive to "spelling": the description "G4 double sharp" refers to the same pitch as A4; in other temperaments, these may be distinct pitches. Human perception of musical intervals is approximately logarithmic with respect to fundamental frequency: the perceived interval between the pitches "A220" and "A440" is the same as the perceived interval between the pitches A440 and A880. Motivated by this logarithmic perception, music theorists sometimes represent pitches using a numerical scale based on the logarithm of fundamental frequency. For example, one can adopt the widely used MIDI standard to map fundamental frequency, f, to a real number, p, as follows


Temporal theories offer an alternative that appeals to the temporal structure of action potentials, mostly the phase-locking and mode-locking of action potentials to frequencies in a stimulus. The precise way this temporal structure helps code for pitch at higher levels is still debated, but the processing seems to be based on an autocorrelation of action potentials in the auditory nerve. However, it has long been noted that a neural mechanism that may accomplish a delay—a necessary operation of a true autocorrelation—has not been found. At least one model shows that a temporal delay is unnecessary to produce an autocorrelation model of pitch perception, appealing to phase shifts between cochlear filters; however, earlier work has shown that certain sounds with a prominent peak in their autocorrelation function do not elicit a corresponding pitch percept, and that certain sounds without a peak in their autocorrelation function nevertheless elicit a pitch. To be a more complete model, autocorrelation must therefore apply to signals that represent the output of the cochlea, as via auditory-nerve interspike-interval histograms. Some theories of pitch perception hold that pitch has inherent octave ambiguities, and therefore is best decomposed into a pitch chroma, a periodic value around the octave, like the note names in western music—and a pitch height, which may be ambiguous, that indicates the octave the pitch is in.


The motif of the England national football team has three lions passant guardant, the emblem of King Richard I, who reigned from 1189 to 1199. The lions, often blue, have had minor changes to colour and appearance. Initially topped by a crown, this was removed in 1949 when the FA was given an official coat of arms by the College of Arms; this introduced ten Tudor roses, one for each of the regional branches of the FA. Since 2003, England top their logo with a star to recognise their World Cup win in 1966; this was first embroidered onto the left sleeve of the home kit, and a year later was moved to its current position, first on the away shirt.


Although England's first away kits were blue, England's traditional away colours are red shirts, white shorts and red socks. In 1996, England's away kit was changed to grey shirts, shorts and socks. This kit was only worn three times, including against Germany in the semi-final of Euro 96 but the deviation from the traditional red was unpopular with supporters and the England away kit remained red until 2011, when a navy blue away kit was introduced. The away kit is also sometimes worn during home matches, when a new edition has been released to promote it.


England failed to qualify for the World Cup in 1974, 1978 and 1994. The team's earliest exit in the competition itself was its elimination in the first round in 1950, 1958 and most recently in the 2014 FIFA World Cup, after being defeated in both their opening two matches for the first time, versus Italy and Uruguay in Group D. In 1950, four teams remained after the first round, in 1958 eight teams remained and in 2014 sixteen teams remained. In 2010, England suffered its most resounding World Cup defeat (4–1 to Germany) in the Round of 16, after drawing with the United States and Algeria and defeating Slovenia 1–0 in the group stage.


Their first ever defeat on home soil to a foreign team was an 0–2 loss to the Republic of Ireland, on 21 September 1949 at Goodison Park. A 6–3 loss in 1953 to Hungary, was their second defeat by a foreign team at Wembley. In the return match in Budapest, Hungary won 7–1. This still stands as England's worst ever defeat. After the game, a bewildered Syd Owen said, "it was like playing men from outer space". In the 1954 FIFA World Cup, England reached the quarter-finals for the first time, and lost 4–2 to reigning champions Uruguay.


In February 2012, Capello resigned from his role as England manager, following a disagreement with the FA over their request to remove John Terry from team captaincy after accusations of racial abuse concerning the player. Following this, there was media speculation that Harry Redknapp would take the job. However, on 1 May 2012, Roy Hodgson was announced as the new manager, just six weeks before UEFA Euro 2012. England managed to finish top of their group, winning two and drawing one of their fixtures, but exited the Championships in the quarter-finals via a penalty shoot-out, this time to Italy.


The England national football team represents England and the Crown Dependencies of Jersey, Guernsey and the Isle of Man for football matches as part of FIFA-authorised events, and is controlled by The Football Association, the governing body for football in England. England are one of the two oldest national teams in football; alongside Scotland, whom they played in the world's first international football match in 1872. England's home ground is Wembley Stadium, London, and the current team manager is Roy Hodgson.


To begin with, England had no permanent home stadium. They joined FIFA in 1906 and played their first ever games against countries other than the Home Nations on a tour of Central Europe in 1908. Wembley Stadium was opened in 1923 and became their home ground. The relationship between England and FIFA became strained, and this resulted in their departure from FIFA in 1928, before they rejoined in 1946. As a result, they did not compete in a World Cup until 1950, in which they were beaten in a 1–0 defeat by the United States, failing to get past the first round in one of the most embarrassing defeats in the team's history.


England is quite a successful nation at the UEFA European Football Championship, having finished in third place in 1968 and reached the semi-final in 1996. England hosted Euro 96 and have appeared in eight UEFA European Championship Finals tournaments, tied for ninth-best. The team has also reached the quarter-final on two recent occasions in 2004 and 2012. The team's worst result in the competition was a first-round elimination in 1980, 1988, 1992 and 2000. The team did not enter in 1960, and they failed to qualify in 1964, 1972, 1976, 1984, and 2008.


England qualified for the 1970 FIFA World Cup in Mexico as reigning champions, and reached the quarter-finals, where they were knocked out by West Germany. England had been 2–0 up, but were eventually beaten 3–2 after extra time. They failed in qualification for the 1974, leading to Ramsey's dismissal, and 1978 FIFA World Cups. Under Ron Greenwood, they managed to qualify for the 1982 FIFA World Cup in Spain (the first time competitively since 1962); despite not losing a game, they were eliminated in the second group stage.


Sven-Göran Eriksson took charge of the team between 2001 and 2006, and was the first non–English manager of England. Despite controversial press coverage of his personal life, Eriksson was consistently popular with the majority of fans.[citation needed] He guided England to the quarter-finals of the 2002 FIFA World Cup, UEFA Euro 2004, and the 2006 FIFA World Cup. He lost only five competitive matches during his tenure, and England rose to an No.4 world ranking under his guidance. His contract was extended by the Football Association by two years, to include UEFA Euro 2008. However, it was terminated by them at the 2006 FIFA World Cup's conclusion.


All England matches are broadcast with full commentary on BBC Radio 5 Live. From the 2008–09 season until the 2017–18 season, England's home and away qualifiers, and friendlies both home and away are broadcast live on ITV (often with the exception of STV, the ITV affiliate in central and northern Scotland). England's away qualifiers for the 2010 World Cup were shown on Setanta Sports until that company's collapse. As a result of Setanta Sports's demise, England's World Cup qualifier in Ukraine on 10 October 2009 was shown in the United Kingdom on a pay-per-view basis via the internet only. This one-off event was the first time an England game had been screened in such a way. The number of subscribers, paying between £4.99 and £11.99 each, was estimated at between 250,000 and 300,000 and the total number of viewers at around 500,000.


England first appeared at the 1950 FIFA World Cup and have appeared in 14 FIFA World Cups, they are tied for sixth-best in terms of number of wins alongside France and Spain. The national team is one of eight national teams to have won at least one FIFA World Cup title. The England team won their first and only World Cup title in 1966. The tournament was played on home soil and England defeated Germany 4–2 in the final. In 1990, England finished in fourth place, losing 2–1 to host nation Italy in the third place play-off after losing on penalties to champions Germany in the semi-final. The team has also reached the quarter-final on two recent occasions in 2002 and 2006. Previously, they reached this stage in 1954, 1962, 1970 and 1986.


In August 1836, two real estate entrepreneurs—Augustus Chapman Allen and John Kirby Allen—from New York, purchased 6,642 acres (26.88 km2) of land along Buffalo Bayou with the intent of founding a city. The Allen brothers decided to name the city after Sam Houston, the popular general at the Battle of San Jacinto, who was elected President of Texas in September 1836. The great majority of slaves in Texas came with their owners from the older slave states. Sizable numbers, however, came through the domestic slave trade. New Orleans was the center of this trade in the Deep South, but there were slave dealers in Houston. Thousands of enslaved African-Americans lived near the city before the Civil War. Many of them near the city worked on sugar and cotton plantations, while most of those in the city limits had domestic and artisan jobs. In 1860 forty-nine percent of the city's population was enslaved. A few slaves, perhaps as many as 2,000 between 1835 and 1865, came through the illegal African trade. Post-war Texas grew rapidly as migrants poured into the cotton lands of the state. They also brought or purchased enslaved African Americans, whose numbers nearly tripled in the state from 1850 to 1860, from 58,000 to 182,566.


When World War II started, tonnage levels at the port decreased and shipping activities were suspended; however, the war did provide economic benefits for the city. Petrochemical refineries and manufacturing plants were constructed along the ship channel because of the demand for petroleum and synthetic rubber products by the defense industry during the war. Ellington Field, initially built during World War I, was revitalized as an advanced training center for bombardiers and navigators. The Brown Shipbuilding Company was founded in 1942 to build ships for the U.S. Navy during World War II. Due to the boom in defense jobs, thousands of new workers migrated to the city, both blacks and whites competing for the higher-paying jobs. President Roosevelt had established a policy of non-discrimination for defense contractors, and blacks gained some opportunities, especially in shipbuilding, although not without resistance from whites and increasing social tensions that erupted into occasional violence. Economic gains of blacks who entered defense industries continued in the postwar years.


One wave of the population boom ended abruptly in the mid-1980s, as oil prices fell precipitously. The space industry also suffered in 1986 after the Space Shuttle Challenger disintegrated shortly after launch. There was a cutback in some activities for a period. In the late 1980s, the city's economy suffered from the nationwide recession. After the early 1990s recession, Houston made efforts to diversify its economy by focusing on aerospace and health care/biotechnology, and reduced its dependence on the petroleum industry. Since the increase of oil prices in the 2000s, the petroleum industry has again increased its share of the local economy.


Underpinning Houston's land surface are unconsolidated clays, clay shales, and poorly cemented sands up to several miles deep. The region's geology developed from river deposits formed from the erosion of the Rocky Mountains. These sediments consist of a series of sands and clays deposited on decaying organic marine matter, that over time, transformed into oil and natural gas. Beneath the layers of sediment is a water-deposited layer of halite, a rock salt. The porous layers were compressed over time and forced upward. As it pushed upward, the salt dragged surrounding sediments into salt dome formations, often trapping oil and gas that seeped from the surrounding porous sands. The thick, rich, sometimes black, surface soil is suitable for rice farming in suburban outskirts where the city continues to grow.


In the 1960s, Downtown Houston consisted of a collection of mid-rise office structures. Downtown was on the threshold of an energy industry–led boom in 1970. A succession of skyscrapers were built throughout the 1970s—many by real estate developer Gerald D. Hines—culminating with Houston's tallest skyscraper, the 75-floor, 1,002-foot (305 m)-tall JPMorgan Chase Tower (formerly the Texas Commerce Tower), completed in 1982. It is the tallest structure in Texas, 15th tallest building in the United States, and the 85th tallest skyscraper in the world, based on highest architectural feature. In 1983, the 71-floor, 992-foot (302 m)-tall Wells Fargo Plaza (formerly Allied Bank Plaza) was completed, becoming the second-tallest building in Houston and Texas. Based on highest architectural feature, it is the 17th tallest in the United States and the 95th tallest in the world. In 2007, downtown Houston had over 43 million square feet (4,000,000 m²) of office space.


In 2006, the Houston metropolitan area ranked first in Texas and third in the U.S. within the Category of "Best Places for Business and Careers" by Forbes magazine. Foreign governments have established 92 consular offices in Houston's metropolitan area, the third highest in the nation. Forty foreign governments maintain trade and commercial offices here and 23 active foreign chambers of commerce and trade associations. Twenty-five foreign banks representing 13 nations operate in Houston, providing financial assistance to the international community.


Many annual events celebrate the diverse cultures of Houston. The largest and longest running is the annual Houston Livestock Show and Rodeo, held over 20 days from early to late March, is the largest annual livestock show and rodeo in the world. Another large celebration is the annual night-time Houston Pride Parade, held at the end of June. Other annual events include the Houston Greek Festival, Art Car Parade, the Houston Auto Show, the Houston International Festival, and the Bayou City Art Festival, which is considered to be one of the top five art festivals in the United States.


Of the 10 most populous U.S. cities, Houston has the most total area of parks and green space, 56,405 acres (228 km2). The city also has over 200 additional green spaces—totaling over 19,600 acres (79 km2) that are managed by the city—including the Houston Arboretum and Nature Center. The Lee and Joe Jamail Skatepark is a public skatepark owned and operated by the city of Houston, and is one of the largest skateparks in Texas consisting of 30,000 (2,800 m2) square foot in-ground facility. The Gerald D. Hines Waterwall Park—located in the Uptown District of the city—serves as a popular tourist attraction, weddings, and various celebrations. A 2011 study by Walk Score ranked Houston the 23rd most walkable of the 50 largest cities in the United States. Wet'n'Wild SplashTown is a water park located north of Houston.


The city of Houston has a strong mayoral form of municipal government. Houston is a home rule city and all municipal elections in the state of Texas are nonpartisan. The City's elected officials are the mayor, city controller and 16 members of the Houston City Council. The current mayor of Houston is Sylvester Turner, a Democrat elected on a nonpartisan ballot. Houston's mayor serves as the city's chief administrator, executive officer, and official representative, and is responsible for the general management of the city and for seeing that all laws and ordinances are enforced.


The Houston–The Woodlands–Sugar Land metropolitan area is served by one public television station and two public radio stations. KUHT (HoustonPBS) is a PBS member station and is the first public television station in the United States. Houston Public Radio is listener-funded and comprises two NPR member stations: KUHF (KUHF News) and KUHA (Classical 91.7). KUHF is news/talk radio and KUHA is a classical music station. The University of Houston System owns and holds broadcasting licenses to KUHT, KUHF, and KUHA. The stations broadcast from the Melcher Center for Public Broadcasting, located on the campus of the University of Houston.


Houston (i/ˈhjuːstən/ HYOO-stən) is the most populous city in Texas and the fourth most populous city in the United States, located in Southeast Texas near the Gulf of Mexico. With a census-estimated 2014 population of 2.239 million people, within a land area of 599.6 square miles (1,553 km2), it also is the largest city in the Southern United States, as well as the seat of Harris County. It is the principal city of Houston–The Woodlands–Sugar Land, which is the fifth most populated metropolitan area in the United States.


By 1860, Houston had emerged as a commercial and railroad hub for the export of cotton. Railroad spurs from the Texas inland converged in Houston, where they met rail lines to the ports of Galveston and Beaumont. During the American Civil War, Houston served as a headquarters for General John Bankhead Magruder, who used the city as an organization point for the Battle of Galveston. After the Civil War, Houston businessmen initiated efforts to widen the city's extensive system of bayous so the city could accept more commerce between downtown and the nearby port of Galveston. By 1890, Houston was the railroad center of Texas.


In August 2005, Houston became a shelter to more than 150,000 people from New Orleans who evacuated from Hurricane Katrina. One month later, approximately 2.5 million Houston area residents evacuated when Hurricane Rita approached the Gulf Coast, leaving little damage to the Houston area. This was the largest urban evacuation in the history of the United States. In September 2008, Houston was hit by Hurricane Ike. As many as forty percent refused to leave Galveston Island because they feared the traffic problems that happened after Hurricane Rita.


Though Houston is the largest city in the United States without formal zoning regulations, it has developed similarly to other Sun Belt cities because the city's land use regulations and legal covenants have played a similar role. Regulations include mandatory lot size for single-family houses and requirements that parking be available to tenants and customers. Such restrictions have had mixed results. Though some have blamed the city's low density, urban sprawl, and lack of pedestrian-friendliness on these policies, the city's land use has also been credited with having significant affordable housing, sparing Houston the worst effects of the 2008 real estate crisis. The city issued 42,697 building permits in 2008 and was ranked first in the list of healthiest housing markets for 2009.


The Houston area is a leading center for building oilfield equipment. Much of its success as a petrochemical complex is due to its busy ship channel, the Port of Houston. In the United States, the port ranks first in international commerce and tenth among the largest ports in the world. Unlike most places, high oil and gasoline prices are beneficial for Houston's economy, as many of its residents are employed in the energy industry. Houston is the beginning or end point of numerous oil, gas, and products pipelines:


The Houston Theater District, located downtown, is home to nine major performing arts organizations and six performance halls. It is the second-largest concentration of theater seats in a downtown area in the United States. Houston is one of few United States cities with permanent, professional, resident companies in all major performing arts disciplines: opera (Houston Grand Opera), ballet (Houston Ballet), music (Houston Symphony Orchestra), and theater (The Alley Theatre). Houston is also home to folk artists, art groups and various small progressive arts organizations. Houston attracts many touring Broadway acts, concerts, shows, and exhibitions for a variety of interests. Facilities in the Theater District include the Jones Hall—home of the Houston Symphony Orchestra and Society for the Performing Arts—and the Hobby Center for the Performing Arts.


The Theater District is a 17-block area in the center of downtown Houston that is home to the Bayou Place entertainment complex, restaurants, movies, plazas, and parks. Bayou Place is a large multilevel building containing full-service restaurants, bars, live music, billiards, and Sundance Cinema. The Bayou Music Center stages live concerts, stage plays, and stand-up comedy. Space Center Houston is the official visitors' center of NASA's Lyndon B. Johnson Space Center. The Space Center has many interactive exhibits including moon rocks, a shuttle simulator, and presentations about the history of NASA's manned space flight program. Other tourist attractions include the Galleria (Texas's largest shopping mall, located in the Uptown District), Old Market Square, the Downtown Aquarium, and Sam Houston Race Park.


Minute Maid Park (home of the Astros) and Toyota Center (home of the Rockets), are located in downtown Houston. Houston has the NFL's first retractable-roof stadium with natural grass, NRG Stadium (home of the Texans). Minute Maid Park is also a retractable-roof stadium. Toyota Center also has the largest screen for an indoor arena in the United States built to coincide with the arena's hosting of the 2013 NBA All-Star Game. BBVA Compass Stadium is a soccer-specific stadium for the Dynamo, the Texas Southern University football team, and Dash, located in East Downtown. In addition, NRG Astrodome was the first indoor stadium in the world, built in 1965. Other sports facilities include Hofheinz Pavilion (Houston Cougars basketball), Rice Stadium (Rice Owls football), and Reliant Arena. TDECU Stadium is where the University of Houston Houston Cougars football team plays. Houston has hosted several major sports events: the 1968, 1986 and 2004 Major League Baseball All-Star Games; the 1989, 2006 and 2013 NBA All-Star Games; Super Bowl VIII and Super Bowl XXXVIII, as well as hosting the 2005 World Series and 1981, 1986, 1994 and 1995 NBA Finals, winning the latter two. Super Bowl LI is currently slated to be hosted in NRG Stadium in 2017.


Several private institutions of higher learning—ranging from liberal arts colleges, such as The University of St. Thomas, Houston's only Catholic university, to Rice University, the nationally recognized research university—are located within the city. Rice, with a total enrollment of slightly more than 6,000 students, has a number of distinguished graduate programs and research institutes, such as the James A. Baker Institute for Public Policy. Houston Baptist University, affiliated with the Baptist General Convention of Texas, offers bachelor's and graduate degrees. It was founded in 1960 and is located in the Sharpstown area in Southwest Houston.


Houston is the seat of the internationally renowned Texas Medical Center, which contains the world's largest concentration of research and healthcare institutions. All 49 member institutions of the Texas Medical Center are non-profit organizations. They provide patient and preventive care, research, education, and local, national, and international community well-being. Employing more than 73,600 people, institutions at the medical center include 13 hospitals and two specialty institutions, two medical schools, four nursing schools, and schools of dentistry, public health, pharmacy, and virtually all health-related careers. It is where one of the first—and still the largest—air emergency service, Life Flight, was created, and a very successful inter-institutional transplant program was developed. More heart surgeries are performed at the Texas Medical Center than anywhere else in the world.


Houston was the headquarters of Continental Airlines until its 2010 merger with United Airlines with headquarters in Chicago; regulatory approval for the merger was granted in October of that year. Bush Intercontinental became United Airlines' largest airline hub. The airline retained a significant operational presence in Houston while offering more than 700 daily departures from the city. In early 2007, Bush Intercontinental Airport was named a model "port of entry" for international travelers by U.S. Customs and Border Protection.


Houston's economy has a broad industrial base in energy, manufacturing, aeronautics, and transportation. It is also leading in health care sectors and building oilfield equipment; only New York City is home to more Fortune 500 headquarters within its city limits. The Port of Houston ranks first in the United States in international waterborne tonnage handled and second in total cargo tonnage handled. Nicknamed the Space City, Houston is a global city, with strengths in business, international trade, entertainment, culture, media, fashion, science, sports, technology, education, medicine and research. The city has a population from various ethnic and religious backgrounds and a large and growing international community. Houston is the most diverse city in Texas and has been described as the most diverse in the United States. It is home to many cultural institutions and exhibits, which attract more than 7 million visitors a year to the Museum District. Houston has an active visual and performing arts scene in the Theater District and offers year-round resident companies in all major performing arts.


Houston has mild winters in contrast to most areas of the United States. In January, the normal mean temperature at Intercontinental Airport is 53.1 °F (11.7 °C), while that station has an average of 13 days with a low at or below freezing. Snowfall is rare. Recent snow events in Houston include a storm on December 24, 2004 when one inch (2.5 cm) of snow accumulated in parts of the metro area. Falls of at least one inch on both December 10, 2008 and December 4, 2009 marked the first time measurable snowfall had occurred in two consecutive years in the city's recorded history. The coldest temperature officially recorded in Houston was 5 °F (−15 °C) on January 18, 1940. Houston has historically received an ample amount of rainfall, averaging about 49.8 in (1,260 mm) annually per 1981–2010 normals. Localized flooding often occurs, owing to the extremely flat topography and widespread typical clay-silt prairie soils, which do not drain quickly.


The University of Houston System's annual impact on the Houston area's economy equates to that of a major corporation: $1.1 billion in new funds attracted annually to the Houston area, $3.13 billion in total economic benefit and 24,000 local jobs generated. This is in addition to the 12,500 new graduates the U.H. System produces every year who enter the workforce in Houston and throughout the state of Texas. These degree-holders tend to stay in Houston. After five years, 80.5% of graduates are still living and working in the region.


Houston was founded in 1836 on land near the banks of Buffalo Bayou (now known as Allen's Landing) and incorporated as a city on June 5, 1837. The city was named after former General Sam Houston, who was president of the Republic of Texas and had commanded and won at the Battle of San Jacinto 25 miles (40 km) east of where the city was established. The burgeoning port and railroad industry, combined with oil discovery in 1901, has induced continual surges in the city's population. In the mid-twentieth century, Houston became the home of the Texas Medical Center—the world's largest concentration of healthcare and research institutions—and NASA's Johnson Space Center, where the Mission Control Center is located.


Located in the American South, Houston is a diverse city with a large and growing international community. The metropolitan area is home to an estimated 1.1 million (21.4 percent) residents who were born outside the United States, with nearly two-thirds of the area's foreign-born population from south of the United States–Mexico border. Additionally, more than one in five foreign-born residents are from Asia. The city is home to the nation's third-largest concentration of consular offices, representing 86 countries.


In 1900, after Galveston was struck by a devastating hurricane, efforts to make Houston into a viable deep-water port were accelerated. The following year, oil discovered at the Spindletop oil field near Beaumont prompted the development of the Texas petroleum industry. In 1902, President Theodore Roosevelt approved a $1 million improvement project for the Houston Ship Channel. By 1910 the city's population had reached 78,800, almost doubling from a decade before. African-Americans formed a large part of the city's population, numbering 23,929 people, or nearly one-third of the residents.


According to the United States Census Bureau, the city has a total area of 656.3 square miles (1,700 km2); this comprises 634.0 square miles (1,642 km2) of land and 22.3 square miles (58 km2) of water. The Piney Woods is north of Houston. Most of Houston is located on the gulf coastal plain, and its vegetation is classified as temperate grassland and forest. Much of the city was built on forested land, marshes, swamp, or prairie which resembles the Deep South, and are all still visible in surrounding areas. Flatness of the local terrain, when combined with urban sprawl, has made flooding a recurring problem for the city. Downtown stands about 50 feet (15 m) above sea level, and the highest point in far northwest Houston is about 125 feet (38 m) in elevation. The city once relied on groundwater for its needs, but land subsidence forced the city to turn to ground-level water sources such as Lake Houston, Lake Conroe and Lake Livingston. The city owns surface water rights for 1.20 billion gallons of water a day in addition to 150 million gallons a day worth of groundwater.


During the summer months, it is common for temperatures to reach over 90 °F (32 °C), with an average of 106.5 days per year, including a majority from June to September, with a high of 90 °F or above and 4.6 days at or over 100 °F (38 °C). However, humidity usually yields a higher heat index. Summer mornings average over 90 percent relative humidity. Winds are often light in the summer and offer little relief, except in the far southeastern outskirts near the Gulf coast and Galveston. To cope with the strong humidity and heat, people use air conditioning in nearly every vehicle and building. In 1980, Houston was described as the "most air-conditioned place on earth". Officially, the hottest temperature ever recorded in Houston is 109 °F (43 °C), which was reached both on September 4, 2000 and August 28, 2011.


Houston is considered to be a politically divided city whose balance of power often sways between Republicans and Democrats. Much of the city's wealthier areas vote Republican while the city's working class and minority areas vote Democratic. According to the 2005 Houston Area Survey, 68 percent of non-Hispanic whites in Harris County are declared or favor Republicans while 89 percent of non-Hispanic blacks in the area are declared or favor Democrats. About 62 percent Hispanics (of any race) in the area are declared or favor Democrats. The city has often been known to be the most politically diverse city in Texas, a state known for being generally conservative. As a result, the city is often a contested area in statewide elections. In 2009, Houston became the first US city with a population over 1 million citizens to elect a gay mayor, by electing Annise Parker.


According to the 2010 Census, whites made up 51% of Houston's population; 26% of the total population were non-Hispanic whites. Blacks or African Americans made up 25% of Houston's population. American Indians made up 0.7% of the population. Asians made up 6% (1.7% Vietnamese, 1.3% Chinese, 1.3% Indian, 0.9% Pakistani, 0.4% Filipino, 0.3% Korean, 0.1% Japanese), while Pacific Islanders made up 0.1%. Individuals from some other race made up 15.2% of the city's population, of which 0.2% were non-Hispanic. Individuals from two or more races made up 3.3% of the city. At the 2000 Census, there were 1,953,631 people and the population density was 3,371.7 people per square mile (1,301.8/km²). The racial makeup of the city was 49.3% White, 25.3% African American, 5.3% Asian, 0.7% American Indian, 0.1% Pacific Islander, 16.5% from some other race, and 3.1% from two or more races. In addition, Hispanics made up 37.4% of Houston's population while non-Hispanic whites made up 30.8%, down from 62.4% in 1970.


The Houston–The Woodlands–Sugar Land MSA's gross domestic product (GDP) in 2012 was $489 billion, making it the fourth-largest of any metropolitan area in the United States and larger than Austria's, Venezuela's, or South Africa's GDP. Only 26 countries other than the United States have a gross domestic product exceeding Houston's regional gross area product (GAP). In 2010, mining (which consists almost entirely of exploration and production of oil and gas in Houston) accounted for 26.3% of Houston's GAP up sharply in response to high energy prices and a decreased worldwide surplus of oil production capacity, followed by engineering services, health services, and manufacturing.


The Baylor College of Medicine has annually been considered within the top ten medical schools in the nation; likewise, the MD Anderson Cancer Center has consistently ranked as one of the top two U.S. hospitals specializing in cancer care by U.S. News & World Report since 1990. The Menninger Clinic, a renowned psychiatric treatment center, is affiliated with Baylor College of Medicine and The Methodist Hospital System. With hospital locations nationwide and headquarters in Houston, the Triumph Healthcare hospital system is the third largest long term acute care provider nationally.


In 2013, Houston was identified as the #1 U.S. city for job creation by the U.S. Bureau of Statistics after it was not only the first major city to regain all the jobs lost in the preceding economic downturn, but after the crash, more than two jobs were added for every one lost. Economist and vice president of research at the Greater Houston Partnership Patrick Jankowski attributed Houston's success to the ability of the region's real estate and energy industries to learn from historical mistakes. Furthermore, Jankowski stated that "more than 100 foreign-owned companies relocated, expanded or started new businesses in Houston" between 2008 and 2010, and this openness to external business boosted job creation during a period when domestic demand was problematically low. Also in 2013, Houston again appeared on Forbes' list of Best Places for Business and Careers.


Three community college districts exist with campuses in and around Houston. The Houston Community College System serves most of Houston. The northwestern through northeastern parts of the city are served by various campuses of the Lone Star College System, while the southeastern portion of Houston is served by San Jacinto College, and a northeastern portion is served by Lee College. The Houston Community College and Lone Star College systems are within the 10 largest institutions of higher learning in the United States.


METRO began light rail service on January 1, 2004, with the inaugural track ("Red Line") running about 8 miles (13 km) from the University of Houston–Downtown (UHD), which traverses through the Texas Medical Center and terminates at NRG Park. METRO is currently in the design phase of a 10-year expansion plan that will add five more lines. and expand the current Red Line. Amtrak, the national passenger rail system, provides service three times a week to Houston via the Sunset Limited (Los Angeles–New Orleans), which stops at a train station on the north side of the downtown area. The station saw 14,891 boardings and alightings in fiscal year 2008. In 2012, there was a 25 percent increase in ridership to 20,327 passengers embarking from the Houston Amtrak station.


The second-largest commercial airport is William P. Hobby Airport (named Houston International Airport until 1967) which operates primarily short- to medium-haul domestic flights. However, in 2015 Southwest Airlines launched service from a new international terminal at Hobby airport to several destinations in Mexico, Central America, and the Caribbean. These were the first international flights flown from Hobby since 1969. Houston's aviation history is showcased in the 1940 Air Terminal Museum located in the old terminal building on the west side of the airport. Hobby Airport has been recognized with two awards for being one of the top five performing airports in the world and for customer service by Airports Council International.


The Houston area has over 150 active faults (estimated to be 300 active faults) with an aggregate length of up to 310 miles (500 km), including the Long Point–Eureka Heights fault system which runs through the center of the city. There have been no significant historically recorded earthquakes in Houston, but researchers do not discount the possibility of such quakes having occurred in the deeper past, nor occurring in the future. Land in some areas southeast of Houston is sinking because water has been pumped out of the ground for many years. It may be associated with slip along the faults; however, the slippage is slow and not considered an earthquake, where stationary faults must slip suddenly enough to create seismic waves. These faults also tend to move at a smooth rate in what is termed "fault creep", which further reduces the risk of an earthquake.