Black and white image of the construction phase of the Boulder Canyon Project, also known as Hoover Dam. This image features a horse team outfit at the Boulder City branch of the Los Angeles and Salt Lake Railroad.

A colored postcard showing an artist's representation of the transportation of a pipe necessary for the construction of Boulder Dam, a title that was later changed to Hoover Dam. Transcribed onto the top border of the image: "Transporting Pipe, Boulder Dam."

A view of the downstream face of Hoover Dam; from this angle, the power house can be seen at the base of the dam, along with diversion tunnel portals located in the foreground and cable wires suspended over the face of the dam.

A view of the interior of Boulder Dam, as seen from a visitor viewpoint platform; a man leans against the railing, looking down at power generators below. Boulder Dam was officially renamed Hoover Dam in 1947.

An image of the Hoover Dam outlet works. Visible in in the center of the image, people can be seen being lowered into the canyon on a scaffold. Note: Boulder Dam was officially renamed Hoover Dam in 1947.

Postcard showing the site in Black Canyon where Hoover Dam was originally meant to be built. The name evolved from "Black Canyon Dam" to "Boulder Dam" and was officially named Hoover Dam in the late 1940s. Note on front of post card: "Looking upstream Colorado river Black Canyon Dam Site"; Handwritten note and diagram on back of photo: "Hold this to light and you can get some idea of dimensions of dam."

An image of the Boulder Dam intake towers from the Arizona side. Transcribed from front of postcard: "Boulder Dam - Upstream Face." Boulder Dam was officially renamed Hoover Dam in 1947.