“Hoover Dam is a concretearch-gravity dam in the Black Canyon of the Colorado River, on the border between the U.S. states of Nevada and Arizona. 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. Originally known as Boulder Damfrom 1933, it was officially renamed Hoover Dam, for PresidentHerbert Hoover, by a joint resolution of Congress in 1947. ” (https://en.wikipedia.org/wiki/Hoover_Dam)
We visited the Hoover Dam 6.april 2019. It was an amazing view. The Dam is so big that it´s difficult to believe that it is possible to built anything like that.