The Tuol Sleng Genocide Museum  is a former high school which was used as the notorious Security Prison 21 (S-21) by the Khmer Rouge regime (1975 to 1979).

S-21 was  one of at least 150 execution centers in Cambodia at the time, and it is believed that as many as 20,000 prisoners were killed there.  Whilst out of respect for what had happened here, you feel disinclined to take too many photos (the atmosphere reminded me of my visits to Nazi concentration camps), it is VERY important that the story is told, so this site and the Killing Fields (a number of sites in Cambodia where large numbers of people were killed and buried by the Khmer Rouge regime) exist.

I won’t harp on about the atrocities which were undertaken by the Khmer Rouge Regime (there is plenty of information about S-21 on Wikipedia and about the Killing Fields), but to me the most frightening thing is that this all happened within  my lifetime .  It is hard to fathom that anyone could treat other humans in this way.