How They Turned the Colorado River to Build Hoover Dam

To build Hoover Dam, the builders first had to move the Colorado River out of its own canyon, through four tunnels bored in the rock. Then they had to pour a dam so big that, in one piece, it would have taken an estimated 125 years to cool. This documentary follows how they did it, from the federal records of the project, and why they finished nearly two years early. Chapters: 0:00 Introduction 0:49 A River Nobody Could Trust 2:16 Moving the Colorado 3:50 Men on Ropes 4:57 Concrete That Would Not Cool 6:30 Twenty-One Thousand Men 7:30 Two Years Early