The Three Gorges Dam is the largest hydro-electric project in the world at present. When completed, it will be 2,150 meters across and stand 185 meters above the Yangtze, the world's third longest river. Its reservoir would be over 600 kilometers long and force the displacement of as many as 1.9 million people. Construction began in 1994 and is scheduled to take 20 years; the project is now expected to cost over US$24 billion. There are many arguments for and against this project.