Archival objects in this container: Interior of water treatment plant in Boulder City, Nevada: photographic print and negative, approximately 1930 to 1935 Railroad going to the dam site: photographic print, approximately 1930 to 1934 Truck delivery of dynamite and blasting powder: photographic print and negative, approximately 1930 to 1934 Train and railcars at the end of track: photographic print and negative, 1931 Trains dumping debris into railroad cars: photographic print, approximately 1930 to 1932 Bridge in the lower canyon below diversion tunnels: photographic print, approximately 1931 to 1932 Blasting rock upstream of dam site: photographic print, approximately 1931 to 1932 Close up of suspension footbridge across Colorado River: photographic print and negative, 1931 Blasting rock at dam site before cofferdam was built: photographic print and negative, approximately 1931 to 1932 Blasting rock to put anchors in place, cameraman on foreground: photographic print and negative, approximately 1931 to 1932 Blasting rock at noon to put anchors in place, cameraman in foreground: photographic print and negative, approximately 1931 to 1932 Blasting rock with overhead cables in view: photographic print, approximately 1931 to 1932 View of Black Canyon during dam construction: photographic print, approximately 1931 to 1932 Colorado River before construction of diversion tunnels: photographic print, approximately 1931 to 1932 Downstream dumps for tunnel debris: photographic print and negative, approximately 1931 to 1932 Looking upstream from Nevada side before cofferdams were built: photographic print, approximately 1931 to 1932 Construction of cofferdam: photographic print and negative, approximately 1931 to 1932 Construction of cofferdam, fill for cofferdam is visible: photographic print, 1932 Looking downstream at cofferdam construction and diversion tunnels: photographic print, approximately 1932 to 1933 Cofferdam, less than a half mile from dam site: photographic print, 1932 Looking upstream at cofferdam and diversion tunnel from Nevada side: photographic print, approximately 1932 View of cofferdam and diversion tunnel at the bottom of canyon basin: photographic print, approximately 1932 Colorado River drying up after cofferdam was built: photographic print, approximately 1932 Excavation of Black Canyon for dam construction: photographic print, approximately 1932