Tonlé Sap Lake

The Tonlé Sap (បឹងទន្លេសាប) is the largest freshwater lake in Southeast Asia and behaves unlike any other. Each monsoon the Mekong rises so high that it forces the Tonlé Sap river to run backwards, and the lake swells to about five times its dry-season area before draining again, a reversal that drives one of the most productive inland fisheries in the world. Villages on the northern shore live with that movement rather than against it. At Kampong Phluk, sixteen kilometres from Siem Reap, the houses stand on wooden stilts six to eight metres tall and boats pass at window height when the water is up. At Kampong Khleang the stilts are taller still. Prek Toal in the north-west is one of the most important waterbird breeding colonies in Southeast Asia. The whole lake and its floodplain were made a UNESCO biosphere reserve in 1997.