There's a lake that's literally a giant sinkhole - Apparently.
Lake Natron, located in Tanzania, is a saline lake that forms a giant sinkhole due to the evaporation of water and the concentration of minerals. The lake's water is so caustic that it can turn animals that die in it into stone, essentially mummifying them. This unique phenomenon occurs because of the lake's high pH level, which is around 10.5, making it one of the most alkaline bodies of water on Earth.