History of the National Park Service and multi purpose river basin development programs like the Tennessee Valley Authority which began in the 1930s and spread to river valleys in all parts of the country after World War II. Lake Mead was the first National Recreation Area. The Boulder Canyon Project Act, passed in 1928, authorized the Bureau of Reclamation to construct Hoover Dam on the Colorado River. Work began in 1931 and the dam, highest in the Western Hemisphere, was completed in 1935. The next year, under provisions of an agreement with the Bureau of Reclamation, the National Park Service assumed responsibility for all recreational activities
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