This is a man-made lake that was created when the government put in the dam on the right side. The valley used to be inhabitable, and there used to be several villages in the valley, but the Chinese government wanted to build the dam, so they moved all of the villages out of that area, built the dam, and flooded the valley. This theme of moving people to accommodate national will, obviously something that happens in the US to some extent, seemed to be a common one in China. When we went to see the terra-cotta warriors, we found out that the government had moved all of the villagers out after the discovery and built these big high-rises to accommodate them outside of the excavation zone.