From the Morgan Sweeney Photograph Collection (PH-00228). Hoover Dam switchyard, circa 1950s. Stamp on the back reads, "Photograph by Bureau of Reclamation BCP 9187 Boulder Canyon Project Boulder City, Nevada."
Black and white image of Hoover Dam under construction in Black Canyon. Arizona and Nevada can be seen on either side of the dam in this picture. Note: Boulder Dam was officially renamed Hoover Dam in 1947.