Lake Vanda in Wright Valley has what is said to be the clearest ice in the world. The lake water is almost completely chlorophyll and sediment-free and transports light only 10% less than distilled water. While walking across the ice I could see the bottom through solid ice some 7 meters below as if I was looking through a glass-top table. At the lake center, the bottom is 65m down and the bottom water is hypersaline. This salty (10x saltier than seawater) layer traps heat and keeps the bottom water at 25°C year-round, and supports lots of bacteria that live off the incoming sunlight. Above the lake edge in the background, you can see old shorelines from times when the lake level was higher.