Here's a view of the upper part of Hoover Dam from the 3rd level of the parking garage on the Nevada side. The cables you see are those from the power plants below. Hoover Dam sits in the Black Canyon of the Colorado River... on the border between Nevada & Arizona. Construction of the dam was started in 1931 and completed in 1935. The dam is built entirely of solid concrete... approximately 4.5 million cubic yards of it. That is enough concrete to build a 2 lane highway from Seattle, WA to Miami, FL.