On This Day in Construction:

07th July, 1930

Construction of Hoover Dam started.
Hoover Dam is a concrete arch-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 1930 and 1936 during the Great Depression.
About 3.3 million Cubic Yard of concrete was poured to construct the dam!