Black and white photograph of people standing inside a 30 foot penstock pipe (These pipes were used in the diversion tunnels in the construction of Hoover Dam.)
An image of water discharging from open jet flow gates (outlet works) on the Nevada side of Boulder Dam. The name was officially changed to Hoover Dam in 1947.
Black and white image of Old Callville with the following printed description: The deserted town of Old Callville looking downstream. Shows largest building approximately 30' X 120' and built of masonry.