Hoover Dam, once known as Boulder Dam, is a concrete arch-gravity dam in the Black Canyon of the Colorado River, on the border between the US states of Arizona and Nevada.
It was constructed between 1931 and 1936 during the Great Depression and was dedicated on September 30, 1935, by President Franklin D. Roosevelt. Its construction was the result of a massive effort involving thousands of workers, and cost over one hundred lives. The dam was controversially named after President Herbert Hoover.
The Hoover Dam is a curved gravity dam. Lake Mead pushes against the dam, creating compressive forces that travel along the great curved wall. The canyon walls push back, counteracting these forces. This action squeezes the concrete in the arch together, making the dam very rigid. This way, Lake Mead can't push it over.
In other words; this dam is as strong as it can be! Nothing can destroy it! Well… maybe Godzilla, but he is in Japan.