In the Preah Monivong National Park in southern Cambodia, about 20kms from Kampot, is the ghost town Bokor Hill Station. It was built by the French in the 1920s and the main buildings of the Bokor Palace Hotel & Casino as well as the Church are still standing, ready for exploration. Its high in the hills and on the day we visited, a cool, damp mist was floating around which gave it a particularly eerie feeling.
This area was a strong hold of the Khmer Rouge right up until the 1990s.
Its been used as a location for a number of movies, most known to people would be City of Ghosts, starring Matt Dillon.
Although the area has been cleared of landmines (twice) you would be well advised to stay on very worn paths – this goes for much of Cambodia as well as Vietnam and Laos.