Hoover Dam is located on the border of Arizona and Nevada. The dam is 30 miles southeast of Las Vegas. It was named after President Herbert Hoover. He played a major part in the construction of the dam. The construction began in 1931 and was finished two years ahead of schedule, in 1936. The dam is listed as a National Historic Landmark.
If you are anywhere near Las Vegas, it will certainly be worth your while to take a tour.