Three Gorges Dam, 607 ft (185 m) high and 7,575 ft (2,309 m) long, on the Chang (Yangtze) River, central Hubei prov., China, 30 mi (48 km) W of Yichang. The largest concrete structure in the world, the dam itself was constructed from 1994 to 2006. Its hydroelectric station has 32 turbines that can generate 22,500 MW, making it the largest in the world. In 2003 sluice gates were closed to begin flooding the scenic gorges for which the dam was named and filling a reservoir that is 410 mi (660 km) long and holds as much water as Lake Superior; the hydroelectric station became fully functional in 2012. Some 1.3 million people were moved in the process of creating the dam and reservoir.