Hoover Dam
Another incredible feat of modern engineering, the Hoover Damn bears the full weight of the Colorado River, providing hydroelectric power to residents and businesses alike in Arizona, Nevada, and California.
HOOVER DAM, AZ – MARCH 30: A tourist photographs Hoover Dam, impounding the Colorado River at the Arizona-Nevada border, on March 30, 2016. Completed in 1935, the concrete arch-gravity dam is operated by the U.S. Department of the Interior’s Bureau of Reclamation. The popular attraction, which created Lake Mead, was named after former U.S. President Herbert Hoover. (Photo by Robert Alexander/Getty Images)
Constructed from 1931 to 1935, the project took place at the height of the Great Depression. Built by a conglomeration of six different companies (aptly named Six Companies, Inc), the project would cost more than one hundred human lives over its duration, mostly because the entire dam was unprecedented, technologically-speaking. No concrete structure of this size had been built up to this point, and many of the techniques used were untested. All the same, Congress approved the project, and today, it stands as a shining example of our engineering prowess, drawing over a million visits a year from curious tourists.