Without a doubt, the Killing Fields is the hardest place I've ever visited. It's a place erected to remembering the victims of a terrible horror story, and these photos were much more for education than for fun. This is the large structure that greets you when you walk in, and where the tour ends. It's filled with human skulls, of all ages, found in the mass graves.

Inside the structure. The bottom level is clothing, and the rest are skulls.