Tonle Sap

Southeast Asia's largest lake that reverses its river's flow/Water

Tonle Sap is the largest freshwater lake in Southeast Asia, located in Cambodia. It is one of the most unusual hydrological systems on Earth: during the dry season it covers roughly 2,700 square kilometers, but during the monsoon (June through October), the swollen Mekong River actually reverses the flow of the Tonle Sap River, pushing water back into the lake and expanding it to as much as 16,000 square kilometers, roughly six times its dry-season size. This expansion floods surrounding forests and creates one of the world's most productive freshwater fisheries, providing over 60% of Cambodia's protein intake.