Construction workers labored from 1956 to 1964 to build this giant concrete structure. It stands 710 feet high above bedrock, and its top measures 1,560 feet across. Thickness ranges from 300 feet at the base to just 25 feet at the top. As part of the Colorado River Storage Project the dam provides water storage (its main purpose), hydroelectricity, flood control, and recreation on Lake Powell. Eight giant turbine generators churn out a total of 1,150,000 kilowatts at 13,800 volts.

Conservationists deplored the loss of remote and beautiful Glen Canyon of the Colorado River beneath Lake Powell. On the other hand, the 186-mile lake now provides easy access for many people to an area most had not even known existed. Lake Powell is the second largest man-made lake in the United States. Only Lake Mead, farther downstream, has a greater water-storage capacity. Lake Powell, however, has three times more shoreline - 1,960 miles - and holds enough water to cover the state of Pennsylvania a foot deep. The elevation of the surface fluctuates from 3,640 to 3,700 feet.