Originally S 21 prison was Chao Ponhea Yat High School. The buildings were surrounded by mango, coconut and papaya trees. After the communist Khmer Rouge took over Phnom Penh, it was renamed S 21 prison. “S” for Santebal the Khmer meaning for “state security organization” and “21” the former walkie talkie number of the former prison chief. Cambodians were brought here blindfolded and forcefully made to confess to crimes and spying which were never committed.

The Killing Fields were a short drive from the prison. Renamed Choeung Ek Genocidal Center, this was once a beautiful orchard growing longan trees and water melons. A Chinese cemetery was added to small part of the property long before the genocide. Today it is a mass grave of the victims from the genocide. 129 mass graves were found, 86 of which were excavated. 8,985 corpses were exhumed. The largest mass grave was a grave containing 450 corpses. Between 1975-1978, about 20,000 victims including diplomats, foreigners, intellectuals, officers, soldiers, farmers and especially children and women were murdered there. On January 7,1979, the mystery of the killing fields including Choeung Ek (S 21 Prison) were discovered.

The Choeung Ek Genocidal Center is open land filled with large holes in the earth that haven’t grown over since the genocide. Bones and teeth are still resurfacing during rainy seasons. A large memorial has been built that houses skulls and bones. The memorial is divided into 17 levels. The bottom level are the clothing from the victims, then skulls and beyond sight are the larger bones found. There are two areas that have a fence and rooftop over the mass graves. Headless bodies of former Khmer Rouge soldiers lay in one of them, and the remains of 450 people lay in the other.