In the desert of the southwest sits a looming, concrete arch-gravity dam in the Black Canyon of the Colorado River, on the border between 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. It was a massive effort involving thousands of workers, many who lost their lives. Originally known as Boulder Dam, today it provides power for public and private utilities in Nevada, Arizona, and California, and is a major tourist attraction; nearly a million people tour the dam each year.

This week, the Hoover Dam.