From the Morgan Sweeney Photograph Collection (PH-00228). The stone monument reads, "A Modern Civil Engineering Wonder of the United States - One of Seven Selected by the Ameircan Society of Civil Engineers, 1955. Nevada-Arizona."
A section of a penstock pipe arrives at the mouth of an adit leading to the interior of one of the diversion tunnels during the construction of Hoover Dam.
Transmission tower and lines near Hoover Dam. Caption on top of postcard reads: "Boulder Dam power for Arizona! Towers like this will carry low-cost energy into Arizona when this state follows the example afforded by California and Nevada." Boulder Dam was officially re-named Hoover Dam in 1947.