A UNESCO World Heritage Site, Baikal Lake in Russia at 5,387 feet is the world’s deepest, as well as being the oldest lake in the world at 25 million years old. It is 2,000 feet deeper than the Caspian Sea which is the third deepest lake in the world. Endemism occurs in the lake with half of its 60 native fish species and a freshwater seal. Baikal holds 20% of the world’s unfrozen freshwater, which amounts to around 5,662 cubic miles of crystal clear freshwater which is more than what the Great Lakes of North America holds in total volume.