Hoover Dam spans the Colorado River in Black Canyon between Arizona and Nevada, some 30 miles southeast of Las Vegas Nevada. Constructed in the 1930s, the concrete arch-gravity structure was intended to prevent flooding as well as provide much-needed irrigation and hydroelectric power to arid regions of states like California and Arizona. It was originally known as Boulder Dam, but was renamed in 1947 in honor of Herbert Hoover, who as U.S. secretary of commerce and the 31st U.S. president proved instrumental in getting the dam built. At 726 feet high and 1,244 feet long, Hoover Dam was one of the largest man-made structures in the world at the time of its construction, and one of the world's largest producers of hydroelectric power.
