There's a lake that's a natural swimming pool - Apparently.
Lake Natron in Tanzania is a saline lake that is home to thousands of calcified animals that fall into its waters. The lake's high pH level and alkalinity cause the bodies of the dead animals to calcify, turning them into stone. This unique phenomenon has been occurring for centuries, with some estimates suggesting that the lake has been "preserving" animals for up to 10 years, making it a fascinating example of the natural world's ability to create strange and beautiful landscapes.