Frank Crowe, a Six Companies construction superintendent, leaning against a truck with other unidentified individuals probably in Boulder City, Nevada.

Louis R. Douglas signing a document most likely in Boulder City, Nevada.

The caption on the back of the image reads, " "Like grandfather, like father, like son" is an appropriate title for this photograph of Ray Lyman Wilbur II and Ray Lyman Wilbur III, reading the name of Ray Lyman Wilbur I on a bronze plaque at the Hoover Dam. As noted on the plaque, Ray Lyman Wilbur I was secretary of the Interior during President Hoover's administration and played a major role in administrative matters pertaining to the construction of Hoover Dam. His son and grandson, shown here, were visitors to the dam recently and were given a specially-conducted tour by the Bureau of Reclamation's guide service. The father and son reside at 1808 Indiana Street, Vallejo, California. The plaque is on the left hand side of the entrance to the Hoover Dam's Arizona elevator tower through which a third of a million visitors leave the dam and power plant each year following guided tours of this mammoth structure on the Colorado River between Nevada and Arizona. Guided tours of the dam and power plant, starting at the elevator tower on the Nevada side, are available daily to the public between the hours of 8 a.m. to 5 p.m. Ca. 1950's (Bureau of Reclamation photo)."