Built between 1934 and 1938 it is the barrier that forms Lake Havasu and was built by the Bureau of Reclamation. The main purpose of the dam is to store water for the Colorado River Aqueduct and the Central Arizona Project.
It's the deepest dam in the world with 73% of its overal 320 feet below the original riverbed.
No RVs or trucks or trailers can cross the dam anymore (Homeland Security) but you can drive your car and walk around.