The Hoover Dam has been a popular Arizona attraction since it was constructed in 1935. The dam is an engineering marvel on the Colorado River. Visitors can either drive or walk across the dam that stretches across the river for 1,244 feet. Regarded as one of the greatest engineering wonders of the world, Hoover Dam is a popular destination for people visiting Northern Arizona and Las Vegas. If you have time, be sure to take one of the guided tours of the dam to witness its grandeur up close.