The document provides information about hydroelectric power plants and dams. It discusses how hydroelectric power works by converting the potential and kinetic energy of water into electricity. It also outlines the basic components of hydroelectric plants including reservoirs, dams, turbines, and powerhouses. Several examples of large hydroelectric plants and dams from around the world are mentioned like Hoover Dam, Three Gorges Dam, and Itaipu Dam. Key statistics about the world's largest hydroelectric plants by capacity, storage, and height are also summarized in tables.