This massive dam in the Black Canyon of the Colorado River, on the border of Arizona and Nevada, was built between 1931 and 1936, with a large hydroelectric plant generating electricity for many parts of Arizona, California, and Nevada.

Ideas about damming the Colorado River were realized in the early 20th century to solve two problems. The first was that there were regular floods when snow from the Rocky Mountains melted and the rising river levels would cause floods in farming communities; and the second was that a dam could also provide water for the growing city of Los Angeles, and the nearby areas. The major initial problem was that Arizona and Nevada felt that California would probably take up too much water, so the result ...