12 Sep 1936, USA — Original caption: 9/12/1936-Boulder Dam, AZ/NV- An electrical impulse released by President Roosevelt pressing a button across the continent sent 3,600,000 cubic feet of water a minute tumbling through Gigantic Boulder Dam, and put the Colorado River to work generating electrical power. This photo made by Albert Kopec from a Richfield Oil Company plane, shows the Niagara of water from the 12 outlets; six on the Nevada side and six on the Arizona side. — Image by © Bettmann/CORBIS