Hoover Dam Turbines

I did the Hoover Dam plant tour with my brother and they took us down to see the giant turbines that generate electricity for a fair chunk of the Southwest. A couple floors below giant pipes feed the Colorado river through huge metal blades, which spin and turn a huge metal pole in the middle of these turbines (we could see it spinning!). Under the outer layer of the turbine (where it's painted brown) are 4-ton blocks of copper for generating current. Impressive!