High Scalers drill into the canyon wall 500 feet above the Colorado River in Black Canyon at the Hoover Dam site ... from carelessly placed electrical lines. To top it off, workers knew they ...

High Scalers drill into the canyon wall 500 feet above the Colorado River in Black Canyon at the Hoover Dam site ... from carelessly placed electrical lines. To top it off, workers knew they ...

plus a tunnel drilled in the 1930s and a platform that sits on top of a 30-foot-wide water pipe. Both on-site guided tours include stops inside the power plant, but only the Hoover Dam Tour offers ...