CSPAN3 American History TV August 30, 2014
Acrobatic workmen called high scalers prepared the canyon walls for each blast. Suspended on ropes, they drilled holes in the rock and loaded them with dynamite. After each explosion, these daredevils swarmed over the cliffs, prying loose rock and learing the walls of debris. In november 1932, the Colorado River was diverted. Under control for the first time in its history, the river flowed around and past the site. Men in trucks dumped earth and embankment across the canyon below the tunnel openings, forcing the river from its ageold bend through the huge diversion tubes. A second sandert roc...