Hoover Dam

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 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 the building of the dam. 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.

Construction of the dam began in 1930, thousands of prospective workers flooded the region, many of whom had lost their jobs during first years of the Great Depression. A total of 21,000 men worked on constructing the dam (around 5,000 at any one time) and the region's growing population turned Las Vegas from a sleepy town to a bustling city. The massive project proceeded relatively quickly, and by the fall of 1935 the dam was completed.

Hoover Dam was the tallest dam in the world when it was finished, and remained the largest producer of hydroelectric power in the world until 1948. Today, it is no longer the tallest, the largest by volume, or the largest hydroelectric power producer, but it remains among the biggest and best-known dams in the world. A National Historic Landmark, Hoover Dam draws some 7 million tourists a year, and another 10 million visit Lake Mead for boating, sailing, fishing and other recreation.