An image showing a lengthwise view of a penstock pipe in the Hoover Dam powerhouse. Boulder Dam was officially named Hoover Dam in 1947.

Black and white image of an aerial view looking upstream through the Nevada spillway. At the left are two panels of the overflow weir under construction. Note: Boulder Dam was officially renamed Hoover Dam in 1947.

An image of Rotary Club members having lunch at Boulder Dam. Earl Brothers is also present in this photograph. Note: Boulder Dam was officially renamed Hoover Dam in 1947.

An image of Rotary Club members having lunch at Boulder Dam while an unidentified man gives a speech. Note: Boulder Dam was officially renamed Hoover Dam in 1947.

An image of Rotary Club members having lunch at the Boulder Dam. Earl Brothers is also present in this photo. Note: Boulder Dam was officially renamed Hoover Dam in 1947.

Close up of sand classifier in the gravel plant used for the construction of Boulder Dam, now called Hoover Dam. Site Name: Hoover Dam (dam)

From the Morgan Sweeney Photograph Collection (PH-00228). Hoover Dam generator shaft for Unit A-9 enroute to powerplant via 150-ton cableway in 1951.