Low-level concrete mixing plant at the construction site of Boulder Dam, now called Hoover Dam. Picture taken using telephoto lens. Site Name: Hoover Dam (dam)
Black and white image of the gravel testing laboratory at the site of the former Stewart Ranch, also known as the Las Vegas Ranch. Site Name: Las Vegas Ranch (Las Vegas, Nev.)
Black and white image of the gravel testing laboratory at the site of the former Stewart Ranch, also known as the Las Vegas Ranch. Site Name: Las Vegas Ranch (Las Vegas, Nev.)