Lake Baikal

If the rest of the planet’s fresh water disappeared, there would be enough left in Lake Baikal, Russia to supply humanity for 50 years. It is world's oldest (25 million years old) and deepest (over a mile deep) freshwater lake and contains about 23% of the world's fresh surface water. In Mongolian it means "the Nature Lake." Appears the screams about running out of fresh water are a bit premature.