One of the natural wonders of Asia, the 100-kilometre-long freshwater Tonlé Sap lake links the capital Phnom Penh to Siem Reap.

Uniquely, the Tonlé Sap River, a tributary of the Mekong, reverses its flow twice a year - an effect caused by high water levels in the Mekong and seasonal rain that pushes water back up the Tonlé Sap.

During this time its size increases significantly, taking up as much as a seventh of Cambodia's land area at its peak. This process is a blessing for rice farmers and fishing communities who live on floating houses on the lake.

Visits to the floating villages and bird watching for cranes, storks, pelicans and other species are popular activities on scenic river cruises.