Hoover Dam, once known as Boulder 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.
Straddling the Arizona-Nevada border, the graceful curve and art-deco style of the 726ft Hoover Dam contrasts superbly with the stark landscape. Visitors can either take the 30-minute power plant tour or the more in-depth, one-hour Hoover Dam tour.