The Tonlé Sap is unusual for two reasons: its flow changes direction twice a year, and the portion that forms the lake expands and shrinks dramatically with the seasons. From November to May, Cambodia's dry season, the Tonlé Sap drains into the Mekong River at Phnom Penh. However, when the year's heavy rains begin in June, the Tonlé Sap backs up to form an enormous lake.
For those which like an in-depth discovery of a country, the road of the lake, as well as a ballade in boat with the meeting of the villages of sins floating, are visits impossible to circumvent as well as the temples. It is one of the places or one is with the more meadows of the Kampuchean everyday life and their reality. Here, all the life proceeds around water. Very full of fish, paradise of the sinners, it shelters lake villages since the night of times. Most of the goods arrive by the lake and it is the lung of Siem Reap, because the main roads to join the other cities are in too bad condition. It is the largest lake of Kampuchea and its "feeder mother".