Tonle Sap Lake. Also called Boeung Tonle Sap, it is the largest freshwater lake in Southeast Asia and is the second most popular hotspot in Siem Reap, after Angkor Wat. Tonle Sap Lake is well-known for being one of the world’s most vibrant ecosystems. As it is home to a massive number of many different species of wildlife in and around the lake. Besides that, its fascinating local communities and their floating villages are also what attract most tourists.