Surrounded by a cinder-block wall, the late Khmer Rouge dictator's jungle hideout has been comprehensively looted, though you can still see a low brick building whose courtyard hides an underground bunker.
It's about 5km east on the dirt track accessed behind the smugglers' market at the Choam–Chong Sa-Ngam border crossing (when the trail forks at the water-lily lake, take the left-hand track). This narrow part of the track is navigable only by motorbike.