History of the Grand Canyon area stretched along a 278-mile (447 km) segment of the Colorado River from the southern border of Glen Canyon National Recreation Area to the eastern boundary of Lake Mead National Recreation Area. Grand Canyon National Park was designated a World Heritage Site on October 24, 1979. In 1935, Hoover Dam started to impound Lake Mead south of the canyon. Conservationists lost a battle to save upstream Glen Canyon from becoming a reservoir. The Glen Canyon Dam was completed in 1966 to control flooding and to provide water and hydroelectric power. Seasonal variations of high flow and flooding in the spring and
History of Hispanic and Latino Americans in the United States Texas and Louisiana; and in the same year Francisco Vásquez de Coronado led 2,000 Spaniards and Mexican Indians across today's Arizona–Mexico border. Coronado travelled as far as central Kansas, close to the exact geographic center of what is now the continental United States and he was the first European that saw the Canyon´s Colorado. Other Spanish explorers of the US make up a long list that includes among others, Lucas Vásquez de Ayllón, Pánfilo de Narváez, Sebastián Vizcaíno, Juan Rodríguez Cabrillo, Gaspar de Portolà, Pedro Menéndez de Avilés, Álvar Núñez Cabeza de Vaca, Tristán de Luna y Arellano and Juan