Black and white image showing dynamite blasts being fired simultaneously for the locations of the Arizona (left) and Nevada (right) intake towers at Hoover Dam. Note: Boulder Dam was officially renamed Hoover Dam in 1947.

Day shift construction workers for Boulder Dam, now called Hoover Dam, entering transports at the upper portals for their return journey to Boulder City ten miles away. Site Name: Hoover Dam (dam)

A map of the Boulder Dam area showing the Principle Point of Scenic and Historical interest [left], Boulder City (Nev.) [left], 1931-1936

Site of Boulder Dam, 1931 [left], Boating on Boulder Lake famous Fortification Hill in background [right], 1931-1936

High scaling during early constuction at Boulder Dam [left], Transporting men by cableway, Boulder Dam [middle], Boulder Dam dowstream face and power house [right], 1931-1936

Babcock and Wilcox Steel Co., Boulder Dam [left], Section of 30-foot of Penstock pipe on 200-ton trailer, Boulder Dam [right], 1931-1936

An image of an unidentified man standing inside a corridor at Hoover Dam.