A picture of a truck known as "Big Bertha," carrying 150 workers to the Hoover Dam work site.

This photograph has three images. The first one (0272_0026) is a picture of the first bucket of concrete poured in Boulder Dam, June 6, 1933. The handwritten inscription reads, "The first bucket was 'grout' (cement and water) which was spread over surface of pour with steel brooms. All loose rocks have been pried out, and all cracks have been pumped with grout until filled. Some has taken a week of continuously pumping night and day. Each from and pour is supervised by government selected men." The second one (0272_0027) reads, "Excavation for foundation three hundred feet below river bed down to bedrock." The picture is looking upstream, excavation for dam foundation, Boulder Dam photo provided by the Bureau of Reclamation. It also says, "Seen from lookout point above. Trucks struggling up and down the steep grade, reminds you of ants as they attack this giant job. I often wondered where did they put all this dirt and rubble? Brakes were soon worn out and never replaced. Trucks were geared down real low, but you still got a thrill, going downhill. x-marks trussel for rail that will bring concrete from lower mixing plant around the bend where the mts. end in a gentle slope." written as a handwritten inscription. The third one (0272_0028) reads, "Drilling of walls to clean up and to blast off loose slabs on upstream canyon walls. These men climb hand over hand at end of shift, and slide down to work. The art of keeping your balance in a bos'n chair is picked up in a hurry at heights like this. I saw a miner hand a 90 lb. Hammer of his shoulder and climb hand over hand 75 ft. up, until he got past the overhang before he could touch the canyon wall with his feet. It was a side show," written as a handwritten inscription.

This photograph has three images. The first one (0272_0084) reads, "Top of dam about one form wide - everyone getting in each other's way" (duplicate of Image 0272_0016). The second image (0272_0085) reads, "Getting higher and more enormous. Can you see what's swinging on end of No.7 line?" Refers to the arrow at the top right of photo. "(3) tunnels drilled for penstocks that divert water to turbines. So much to tell about, that's shown in this pic. You can see where the turbines will set. The (slot) in middle of dam indicates how much of the dam has been cooled. Notice how dam curves into canyon walls - to brace against weight that will build up behind it." The third image (0272_0086) shows an early view of the enormous amount of excavating being done and tailings to be moved. An inscription reads "Pouring cement on any part of the dam has not begun, only the diversion tunnels and tracks for head tower and tail tower that hi-lines across the channel are connected to" (referring to the arrow at top of photo). The inscription continues "(x) Reeve fell down this tunnel but was cemented at that time. On the dam I never heard anyone being hurt with falling rock. But - most injuries and fatalities occurred building roads to the dam and at the location of dam. No men have been covered up and left in the cement. Nothing but the purest cement went into the construction of dam, maybe a piece of metal if it wasn't oily. About men being buried in the dam is a misconception (sic). Some have been covered up with cement when the bucked dumped out of control, but the men were rushed to first aid and washed off, and treated, but very few injuries."

An image of a man standing atop a wooden platform as he presents a speech for the unveiling of the memorial plaque at Boulder Dam. Positioned behind the man are seated spectators of the event, as well as the curtain-covered memorial plaque.

A close up view of a plaque dedicated to Elwood Mead, Commissioner of the Bureau of Reclamation Department of the Interior, 1924-1936.

An image of an automobile parked next to a barge on the Colorado River in Black Canyon at the Hoover (Boulder) Dam construction site.

This series of photographs documents the historic water overflow at Hoover Dam as seen from the Arizona side of the dam. Taken in August of 1983, this overflow marked the first time the spillways were used during a flood. After initially being filled, the spillways were tested once in August of 1941.