Much of the sculpture at Hoover Dam is the work of Norwegian-born, naturalized American Oskar J.W. Hansen. His most prominent work is a pair of bronze sculptures entitled "Winged Figures of the Republic." The winged figures are 30 feet high. Their shells are 5/8-inch thick, and contain more than 4 tons of statuary bronze. The figures were formed from sand molds weighing 492 tons. They stand on a black, polished base, capped by a 142-foot flagpole.

In order to place the blocks of black diorite without marring their highly polished finish, they were centered on blocks of ice, and guided precisely into place as the ice melted. After the blocks were in place, the flagpole was dropped through a hole in the center block into a predrilled hole in the mountain.

Surrounding the base is a terrazzo floor, inlaid with a star chart, or celestial map. The chart preserves for future generations the date on which President Franklin D. Roosevelt dedicated Hoover Dam, September 30, 1935.

Near the figures and elevated above the floor is a compass, framed by the signs of the zodiac.

These figures guard the plaque designed by Hansen which commemorates the 96 men who officially died during the construction of Hoover Dam. The plaque which originally was on the Arizona side of the dam, reads:

"They died to make the desert bloom. The United States of America will continue to remember that many who toiled here found their final rest while engaged in the building of this dam. The United States of America will continue to remember the services of all who labored to clothe with substance the plans of those who first visioned the building of this dam."

Hansen also created the concrete bas-relief series on both the Nevada and Arizona elevator towers (the two towers in the middle on top of the dam).

The five bas reliefs on the Nevada elevator tower show the benefits of Hoover Dam: flood control, navigation, irrigation, water storage, and power. The five bas reliefs on the Arizona elevator tower depict "the visages of those Indian tribes who have inhabited mountains and plains from ages distant."

Diorama of the Lower Colorado Region Dam System
of which Hoover Dam is a part.

The floor of the turbine room has an intricate mosaic enlaid on the floor.