Even if visiting the Tuol Sleng Genocide Museum is heartbreaking, it is still a must see attraction. Very well kept in its original state, the bleak conditions in which the victims were kept, a visit to S21 is a must to get a glimpse of what Cambodia suffered 35 years ago. I had a very knowledgeable guide who showed us 4 buildings. Higghly recommend Tuol Sleng Genocide Museum!