“ Bon Oum Tuk” is celebrated throughout Cambodia as it marks the end of the monsoon season. The torrential rain of the monsoon causes a natural and unique phenomenon that only occurs in Cambodia – as the mighty Mekong River becomes engorged with monsoon water, it forces the Tonle Sap River to *reverse direction* and flow upstream, away from the sea. This phenomenon makes the Tonle Sap the largest fresh water lake in Southeast Asia and has fed Cambodians for generations. Once the monsoon is over, the river switches direction.
The Water Festival also serves as a celebration of military victories dating back to the times of #Angkor and the #KhmerEmpire. In particular the tradition of brightly coloured boats racing each other is a tribute to the legendary Khmer King Jayavarman VII who repelled foreign invaders from the kingdom in the 12th century.
There are 800-year-old bas reliefs depicting boat races on the stone walls of Bayon and Banteay Chmar. Nowadays the races are for entertainment but in the time of Jayavarman VII they served as a military exercise for the mighty Khmer navy.