When Boulder Dam—as the Hoover Dam was originally called—started operating in 1936, it sent nearly all of its hydroelectic power to Los Angeles, 266 miles away. The cost was less than half that of power generated by oil-fired plants. The sweeping, monolithic structure—1,244 feet long, 660 feet wide at its base, and 45 feet thick at its crest—was built with low-tech deliberation: Concrete was poured in blocks no more than 5 feet in depth. The process took nearly two years and 3,250,000 cubic yards of concrete. The dam rose slowly, because cooling and bonding processes were required to cope with the heat generated by the setting concrete and its subsequent contraction. Contrary to myth, no one was buried in the concrete. But 96 workers died from heat exhaustion and other causes.

Related Links
U. of Virginia: "The Hoover Dam"

PBS: "Hoover Dam"

"Tennessee Valley Authority"