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 1949 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.

More than 200 engineers worked to design the dam. It was the highest concrete arch dam in the United States, and the largest building project ever undertaken by the federal government. By the time construction of Boulder Dam began in 1930, thousands of prospective workers had 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 building the dam over the course of its construction (around 5,000 at any one time) and the region's growing population turned Las Vegas from a sleepy town to a bustling city. Blistering summer heat and a lack of adequate shelter and services combined with difficult and dangerous working conditions to create a volatile situation, and conflicts arose between the construction firm (Six Companies) and dam workers and their families. It was later estimated that 107 workers lost their lives while building the dam. Despite these problems, the massive project proceeded relatively quickly and was completed two years ahead of schedule and millions of dollars below budget.

Building Hoover Dam required more than 5 million barrels of concrete. The finished dam contained enough concrete (4.5 million cubic yards) to build a two-lane highway from Seattle, Washington to Miami, Florida.

Some 12,000 people attended the opening ceremony on September 30, 1935.