Lake Baikal
The Trans-Mongolian-Siberian passes Lake Baikal for 207 kilometres. Lake Baikal is the oldest lake in the world (minimum of 20 million years unlike most other lakes on earth which are 15,000 years old); its surface size is 31,471 sq. km and its maximum depth is 1637 m. It contains almost one-fifth of all the freshwater reserves of our planet. The water is so transparent that you can throw a white disk of 20 cm. in diameter into Baikal and it can be seen down to a depth of 40 metres. During the winter, the ice can be up to 10 metres thick and still transparent.