The Tonle Sap in Cambodia, some 15 kilometers from Siem Reap, is the largest lake in Southeast Asia and one of the most fish-rich inland waters on the planet. From the north, the lake is fed by several tributaries. To the south is the Tonle Sap River, named after the lake, which flows into the Mekong River in Phnom Penh.
In June, a unique natural phenomenon, which is the occasion of the water festival Bon Om Touk, can be observed here, starting with the monsoon rain and the melting water from the Himalayas. The Tonle Sap river changes its direction of flow due to the increased water volume, and it returns only in November, when the water goes back, in the usual course.
The livelihood of one million Cambodians depends directly on this lake. 90% of these residents live in pile dwellings erected in the lake and 10% on houseboats. The floating villages of Tonle Sap are today a frequented tourist attraction. During the dry season, the pile dwellings tower high above the low water of the river. During the monsoon season, the piles disappear entirely under water.