Black and white image of the Hoover Dam tunnel construction site. There are four visible bridges over the Colorado River. Note: Boulder Dam was officially renamed Hoover Dam in 1947.
Black and white image of diversion tunnel #2 on the Nevada side of Hoover Dam. This image shows the groundwork for the tunnel. Note: Boulder Dam was officially renamed Hoover Dam in 1947.
Black and white image of concrete being placed into the side walls of diversion tunnel #4 at Hoover Dam. Note: Boulder Dam was officially renamed Hoover Dam in 1947.
Black and white image of concrete being placed into the side walls of diversion tunnel #4 at Hoover Dam. Note: Boulder Dam was officially renamed Hoover Dam in 1947.
Black and white image of the Union Pacific streamliner brought to the Hoover (Boulder) Dam site with special a train via Six Companies Inc. This corporation was formed through six different companies in order to build the Hoover Dam.
Black and white image of the Union Pacific streamliner brought to the Hoover (Boulder) Dam site with special a train via Six Companies Inc. This corporation was formed through six different companies in order to build the Hoover Dam.