A couple of Chinese cities were flooded to make a lake, and they were forgotten for more than 40 years!
The Qiandao Lake (Thousand Island Lake) is located in Zhejiang China. It's an artificial lake that was made in 1959 after the Chinese completed a hydroelectric power station. To make it, they flooded a valley that was 573 sq km. The lake got its name because it is dotted with 1078 large islands and a few thousand smaller ones.
Although the water from the reservoir is used to make mineral water, it has recently been turned into a tourist attraction because people remembered that there were a couple of cities that were flooded to make way for the reservoir!
Shi Cheng and He Cheng were ancient cities that were built over 1300 years ago and were large business hubs along the Xin'anjiang river. The cities, along with many other towns that were also flooded were forgotten for 40 years until a local tourism office thought up a way to make them into a tourist attraction.
There are currently a bunch of plans in the works, like scuba diving tours or even submarine tours, but the brittle condition the walls could be in is a concern. Check more pics and info on the plans at the source.