Baikal is about 636 km (395 mi) long. It is 20 to 80 km (12 to 50 mi) wide. At its deepest point, it is 1,700 m (5,600 ft) deep. It is the deepest lake on Earth. The lake is a UNESCOWorld Heritage Site. It holds about 20% of the world's unfrozen surface fresh water.