This node is quite detailed, but I would like to add a few points to it.
I recently visited Cambodia and seen the abject poverty and crippling horror of the genocide. We were shown around the Tuol Sleng Museum (otherwise known as S-21) and showed the torture devices used, the pictures of victims, the cells prisoners were kept in and the piles of skulls stacked up high.
That was not what had the greatest impact on me.
Our tour guide, who had survived the Pol Pot regime still had a look of terror in his eyes even though Pol Pot was dead. He had a look of intense loathing and fear and I knew that the psychological wounds would never heal.
But what he said still rings in my ears today. He said "It's important people know."
I suppose the real point I'm trying to make is that, while we may be told that these things happened in Country A or B, we can't really understand what is happening (or happened) until you get close to the people.
The other thing he said, which also saddens me was about the youth of Cambodia and how they don't understand what happened during the time of the Khmer Rouge.