Building the Hoover Dam — construction begins!

Black Canyon came to life with a mighty boom. The best of 70 sites, it shook with the thunder of dynamite as man reshaped its walls to receive the dam. Day after day, the nation's largest steam shovels bit deeper into the layers of blasted rock and [music] hard-packed earth. Week after week, an endless line of trucks carried the waste over miles of new roads to dump it far from the site. [music] Five bridges were built to carry men and materials across the river. And skip loaders suspended from cables shifted workers back and forth to their various jobs.