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Location: Brazil and Paraguay
Completion Date: 1991
Cost: $18 billion
Reservoir Capacity: 1.02 trillion cubic feet
Purpose: Hydroelectric power
Reservoir: Itaipu Reservoir
Engineer(s): International Engineering Company; Itaipu Binacional
Eighteen was a lucky number for engineers working on the Itaipu Dam. The 4.8-mile-long complex of concrete and rockfill dams on the Upper Parana River at the Brazil-Paraguay border has 18 generators, and it took 18 years and $18 billion to build. The main structure, a hollow, concrete gravity dam, has a powerhouse capable of generating 12,600 megawatts of electricity. That's enough to power most of the state of California. In fact, the enormous dam provides 25 percent of Brazil's energy supply and 78 percent of neighboring Paraguay's energy supply. But building one of the largest hydroelectric dams in the world was not easy.
Engineers actually had to shift the course of the seventh largest river in the world, the Parana River, around the construction site before building the Itaipu Dam. It took almost three years for workers to carve a 1.3-mile-long, 300-foot-deep, 490-foot-wide diversion channel for the river. Fifty million tons of earth and rock were removed in the process. The American Society of Civil Engineers recognized this amazing feat and named the Itaipu Dam one of the "Seven Wonders of the Modern World."Here's how this dam stacks up against some of the biggest dams in the world.
(reservoir capacity, in cubic feet)