Course of the Colorado River into the Virgin River, which ran southward through what is now Overton Arm to join the Colorado River near the now-ghost town of St. Thomas, Nevada. At Hoover Dam, the Colorado turns due south through Black Canyon, a direction it will follow for the remainder of its course to the Gulf of California. It passes under the Mike O'Callaghan–Pat Tillman Memorial Bridge (Hoover Dam Bypass), the highest concrete arch bridge in the world, carrying U.S. Route 93 at a height of above the Colorado River. At the end of Black Canyon the Colorado widens into Lake Mohave, created by the
Shasta Dam behind it, the dam was completed to its final shape and the last bucket of concrete was poured on January 2, 1945. During this time, the Shasta Dam powerplant, with a capacity of 379 MW, was also under construction. Five steel penstocks, each in diameter, were installed to provide water to drive the turbines in the power station. The powerhouse was a reinforced concrete structure standing above the river; electricity was first generated there in 1944. The dam was completed at the dawn of 1945. When Shasta was completed, it was the second highest dam in the world – surpassed