Believed to be around 700,000 years old, this crater lake is about 50 metres deep at the deepest point and around 800 metres across.
Aside from the trail around the lake, another 850-metre path takes you up into the forested hill beside the lake and leads to the road from the main entrance.
On the way around there are wide wooden docks to stop off and jump in for a cooling swim. The lake is especially pretty in the late afternoon as the sun sinks behind the rim and the mist rises off the water.
There's a $1.50 entrance fee for foreigners (and another 2,000 riel for a motorbike, 1,000 riel for a bicycle).
Last updated on 4th June, 2012.