It conveys to future generations the brutal history of Cambodia.

Around April 1976, the Khmer Rouge (Cambodian Communist Party) took over school buildings located in the center of Phnom Penh. It was called the S21 (Security Prison 21), it's code name at the time.
People who were considered to be counter-revolutionary were housed here, together with their families, and were tortured and subjected to severe interrogation, and then executed in the Killing Fields.
Is said that between 14,000 to 20,000 people were housed there for between nine months and two years, and only 8 survived.
It was a prison that few came out and alive.

It has become now a museum. It has photos of about 1000 inmates (including boy and girl jailers), and exhibits of torture by a painter who survived. A torture chamber can also be seen here.
Members of the party and the innocent general also fell victim. I can not help feeling the gruesome of the time.
There is also a screening of a documentary film that lasts for about an hour.