USA/NV: Hoover Dam

Hoover Dam was built at the height of Great Depression between 1931 and 1936 mostly as a way to put thousands of unemployed people to work, blocking the Colorado River above Las Vegas and creating an enormous Lake Mead. The concrete arch of the dam is 726 feet / 221 m high and cost nearly $49 million to build (over $700 million in today’s money).