Two unidentified men with construction equipment inside the outlet works at Hoover Dam. Typed label on back of photograph: "Outlet works - Boulder Dam."

A colored postcard showing an artist's representation of an 150 man transport for the Boulder Dam, later renamed Hoover Dam, project in Black Canyon. Transcribed onto the top border of the image: "150 Man Transport, Boulder Dam Project."

The grayscale view of a man working at the Hoover Dam construction site alongside the Colorado River.

Officials in the field conducting a land survey for the Hoover Dam project. From left to right, the men include McDowell, U.S. Reclamation Service Engineer R. C. Thaxton, and Superintendent of Construction for the Six Companies Frank T. Crowe.

A black and white image of Junior Chamber of Commerce members at a meeting in Las Vegas. This photo was taken from a time capsule in the cornerstone of the Union Pacific Railroad station located in Las Vegas. The time capsule was placed there in 1940 and was later retrieved when the building was demolished around 1970.

A black and white image of Las Vegas Rotary Club members in front of a Union Pacific Stages bus in Las Vegas. This photo was taken from a time capsule in the cornerstone of the Union Pacific Railroad station located in Las Vegas. The time capsule was placed there in 1940 and was later retrieved when the building was demolished around 1970.

A black and white image of Union Pacific Depot Park in downtown Las Vegas. The area was bustling with cars and people.