Vasyugan Swamp (in Russia) is the largest swamp in the world. They are located in Western Siberia, between the Ob and Irtysh Rivers. The area of swamp is 53 thousand km². Vasyugan Swamp appeared about 10 thousand years ago and since then constantly increases. The swamp contains huge reserves of peat and counteracts greenhouse effect. Reserves of peat are more than 1 billion tons. Swamp is the main source of fresh water in the region.