Along the Lake Baikal. Lake Baikal is the largest (by volume) freshwater lake in the world, containing roughly 20% of the world's unfrozen surface fresh water. At 1,642 m (5,387 ft), Baikal is the world's deepest lake. It is considered among the world's clearest lakes and is considered the world's oldest lake — at 25 million years. Steam locomotives (class 2-10-0) L-3438 and L-3485 with passenger tourist train on 153 kilometer of "Circum-Baikal Railway". "Russian railways" ("RZD") resumed running tourist trains on "Circum-Baikal Railway" this year. The train goes in period of the summer (may - september) season at the weekend. Price is about 80$.