Illustration of Hoover Dam on a postcard envelope titled, "Boulder Dam and Vicinity."

This series of photographs documents the historic water overflow at Hoover Dam as seen from the Arizona side of the dam. Taken in August of 1983, this overflow marked the first time the spillways were used during a flood. After initially being filled, the spillways were tested once in August of 1941.

This series of photographs documents the historic water overflow at Hoover Dam as seen from the Arizona side of the dam. Taken in August of 1983, this overflow marked the first time the spillways were used during a flood. After initially being filled, the spillways were tested once in August of 1941.

High scalers at Hoover Dam, with the Colorado River visible in the left side of the photo. Located on the back of the postcard is a handwritten description.

Illustration of Hoover Dam as it was being built. The caption reads: "Looking upstream, Colorado River, Boulder Dam."

Postcard with an illustration of Boulder Dam view from Lookout Point. Boulder Dam was later renamed Hoover Dam.

Form K, a group of construction workers, were the first to reach top of Boulder Dam while being built.