The Hoover Dam was completed in 1936 for flood control and water storage, the 726-foot high dam is one of the highest concrete dams ever constructed.  Exhibits and guided tours through the dam and power plant are offered at the Visitor Center.  A scenic overlook provides breathtaking views of the damn, Lake Mead and Black Canyon.  There is a great deal of construction going on due to the Hoover Dam Bypass.  There may be construction delays and some overlooks may be closed.  The dam itself is a massive curved wall, 660 feet thick at the bottom, tapering to 45 feet where the road crosses it at the top. It towers 726 feet above bedrock (about the height of a 60-story skyscraper) and acts as a plug between the canyon walls to hold back up to 9.2 trillion gallons of water in Lake Mead, the reservoir created by its construction. Four concrete intake towers on the lake side drop the water down about 600 feet to drive turbines and create power, after which the water spills out into the river and continues south.

I paid for the tour, but to be honest, I’m not sure you really have to unless you’re very interested in the inner workings of the dam itself. There are some viewpoints and trip down into the dam that are included on the tour, but everything else is accessible for free. If it’s a super hot day, I’d take the tour to take advantage of the A/C, but if it’s cooler out, bypass the tour and just walk around.