We dedicated one day in Phnom Penh to learn about the genocide committed by the Khmer Rouge and it was, as expected, a really disturbing day. I didn't know much about what actually happened until I started reading about it and visiting the sites. The first place we went to was the Killing Fields of Choeung Ek.
The Killing Fields is basically what the name describes - an area of mass graves and also the location where over 17,000 men, women and children were brutally executed. There is a giant white stupa (religious monument) that serves as a memorial to what happened between 1975-1978. Inside the stupa are about 9000 human skulls found during the excavations. Many of the skulls show that some of the prisoners were bludgeoned to death. It was horrifying to tell you the truth. There was also a small museum and several markers along the field that detailed more atrocities committed. It was overwhelming.
After walking around Choeung Ek we went to the Tuol Sleng Museum also called S-21. The building was originally a high school but was turned into a security prison during the rule of the Khmer Rouge. In 1975 Pol Pot, the leader of the Khmer Rouge, used the high school as his center of detention and torture in Cambodia. Most of the prisoners here were executed at the Killing Fields. Prisoners held in S-21 were tortured routinely and forced to admit to plots or conspiracies against the Khmer Rouge. During 1977, S-21 killed about 100 people per day. You can tour the prison and see the actual rooms and bed posts that remain along with several photographs of prisoners. The photos and the documentary film that we saw are definitely not for the faint of heart - the images were haunting and horrifying. It's scary to think that people were doing these things to each other just over 30 years ago.
Most of the other tourists we met along the way advised us not to visit both of these sites in one day but since we were on a tight schedule we decided to do it anyways. After spending a whole day immersed in the history of a genocide, I wouldn't recommend this itinerary either. Visiting both sites was informative and necessary but visiting them both in one day was a little extreme.