The Licancabur volcano (6,014 m) located at the boundary of Chile and Bolivia hosts a lake that is amongst the highest lakes on Earth. The lake environment combines low-oxygen, low atmospheric pressure, and high-UV radiation. Sediments are formed in volcanic material. It is ice-covered most of the year but the bottom water temperature remains above freezing. These conditions make Licancabur a unique analog (comparison) to ancient Martian lakes. The summit lake is about the size of a football field at 90m x 70m x 4.5m.