Photograph of construction of Boulder Dam, showing the mountains on either side, March 17, 1934. Tiny roads wind around the cliffs of the jagged mountains on either side with several clinging close to the water in the foreground and continuing to the construction site at center. These roads run by four tunnels in the mountain side to reach a crowd of parked automobiles and buildings in front of the tall, lightly-colored dam. The site continues behind the dam until it meets the remaining water in the background. Lines extend over the site from large buildings on the left to others on the right. Roadways from these buildings continue over the tops of the mountains into the background.