Grand Coulee Dam is a hydroelectric gravity dam on the Columbia River in the U.S. state of Washington. In the United States, it is the largest electric power producing facility[2] and the largest concrete structure.[3] It is the fifth largest producer of hydroelectricity in the world. The top producing dams are the Three Gorges Dam in China, the Guri Dam in Venezuela, the Itaipu Dam on the border of Paraguay and Brazil, and the Sayano-Shushenskaya Dam in Russia.