Tonlé Sap Lake, not far from Siem Reap, is a popular tourist destination. It is also geological interest because its water changes direction with the dry and rainy season. During the rainy season from June to October, the swelling Mekong River flows into Tonlé Sap Lake, expanding its surface and depth. Then, during the dry season from November to May, the water flows out. Fishing is the way of life here.