Construction of Boulder Dam at night, ca.1930

Photograph of construction of Boulder Dam at night, ca.1930. The ladders which climb the height of the dam at center are spotted with tiny orbs of light that barely illuminate the dark panels of the wall. Many large lamps brighten the busy work site at the base of the dam, however, and beam against the foot of the canyon wall on the right. A large beacon of light shines from a tower which can be seen over the top of the dam on the far left while a smaller light shines from a similar tower on the right