8. Longtan Dam, China (6.4 GW)
Located on the Hongshui River in China's Guangxi Zhuang Autonomous Region, the Longtan bam is more than 700 feet tall — the tallest of its type in the world. The dam contains seven surface spillways, two bottom outlets and an underground power station. The dam's newest hydroelectric turbine was installed in 2009. The project is owned by Longtan Hydropower Development.