The Licancabur volcano (5916 m) which is located at the boundary of Chile and Bolivia hosts the highest and one of the least explored lakes on Earth. The lake environment combines low oxygen, low atmospheric pressure, and high UV radiation. It is ice-covered most of the year but the bottom water temperature remains above freezing.These conditions make Licancabur a unique analog to ancient Martian lakes. Despite the extreme environment, living organisms are thriving in the lake.