The view of a penstock tunnel located within the interior of Boulder Dam. Visitors of the dam stand above a bridge overlooking the tunnel. Boulder Dam was officially renamed Hoover Dam in 1947.

An image of President Roosevelt in his car en route to the dedication of Boulder Dam (officially renamed Hoover Dam in 1947).

An image of Boulder City Rotary Club members sitting at a table at a luncheon held near Boulder Dam (officially renamed Hoover Dam in 1947).

A black and white image of several unidentified men and women associated with the Rotary Club attending the Boulder Dam decennial (officially renamed Hoover Dam in 1947).

A black and white image of unidentified people posing for a group photograph on top of the Boulder Dam powerhouse (officially renamed Hoover Dam in 1947).

The view of the Fortification Hill area of Lake Mead as a visiting boat zips across the lake's surface. Two women dressed in their bathing suits playfully wave to the camera from the deck of the boat, as other visitors aid in directing the boat's path. Transcribed on the side of the boat: "27-J-154."

A large power boat and its passengers at Quartermaster Canyon on Lake Mead.