Hoover Dam All the Secrets of the Engineering Wonder

Hoover Dam is as tall as a 60-story building. It was the highest dam in the world when it was completed in 1935. Its base is as thick as two football fields are long. Each spillway, designed to let floodwaters pass without harming the dam itself, can handle the volume of water that flows over Niagara Falls. The amount of concrete used in building it was enough to pave a road stretching from San Francisco to New York City.