Tuol Sleng Genocide Museum

Listen for a moment. You may hear traffic on the street outside, a motorbike horn, children somewhere nearby. Inside these walls the sound changes. Footsteps echo on tiled floors. Voices drop almost to a whisper. Palm trees stand in a grassy courtyard, and four plain concrete buildings face it. At first glance this could be any school in Phnom Penh. That ordinary look is where the weight of this place begins.

This was a school. Before 1975, these buildings were a high school, with classrooms, a playground and students in uniform. The neighbourhood around it was called Tuol Svay Prey. Today the site is known as Tuol Sleng. In the years of the Khmer Rouge regime, it had another name, Security Prison 21, or simply S-21. As you walk through, please move gently. This is a museum, but it is also a memorial to thousands of people.

Some background helps. On 17 April 1975, Khmer Rouge forces entered Phnom Penh. Within days, they forced almost the entire population out of the city and into the countryside. The movement, led by Pol Pot, wanted to rebuild Cambodia as a radical agrarian society. Money, schools, markets and religion were abolished. Over the next four years, roughly one and a half to two million Cambodians died from execution, starvation, overwork and disease.

In an emptied capital, the regime turned this school into its central prison for people it saw as enemies. Many prisoners were former officials, teachers, students or professionals. As the regime grew more suspicious, it also arrested its own cadres and soldiers. Whole families were sometimes brought here, including children. Most people who entered through these gates were never released. Estimates suggest that somewhere between twelve thousand and twenty thousand prisoners passed through S-21.

The prison commander was Kaing Guek Eav, known as Comrade Duch. He was a former mathematics teacher. Under his direction, the staff kept detailed records. Prisoners were interrogated, often under torture, and forced to write confessions. These confessions usually described invented plots and long lists of names. Those names led to more arrests. The archive this system produced is one reason the site matters so much today.

Now look at the first building as you enter. The ground-floor rooms here held some of the last prisoners. Each room has a metal bed frame and a photograph on the wall. When Vietnamese troops and Cambodian forces reached Phnom Penh in January 1979, they found this prison abandoned in haste. Bodies of the final victims were still in these rooms. The photographs show what the first visitors saw. In the courtyard, a row of white tombs marks the graves of those last victims.

In the courtyard you will also see a tall wooden frame. Before 1975, this was simple exercise equipment for students. Under the Khmer Rouge, guards used it for torture. Nearby stands a board that lists the prison's security rules, translated into English. Read them slowly. They show how prisoners were controlled in every detail, including when they could speak and when they could cry out.

The next building holds what many visitors remember most. Room after room is filled with black-and-white portraits. The prison staff photographed prisoners when they arrived. Some faces look frightened. Some look calm, or confused. A few prisoners are very young. Many wear a numbered tag. Take your time here. Each photograph shows a person with a name, a family and a life before this place. Many of these people are still not identified.

Notice the facades of the buildings as you move between them. Barbed wire covers the open balconies on the upper floors. The guards put it there to stop prisoners from jumping to their deaths to escape interrogation. Inside some classrooms, crude brick walls divide the space into tiny cells, barely wider than a person lying down. On the upper floors, rough wooden cells stand in rows. The original floor tiles, in simple patterns of yellow and white, are still under your feet.

Most prisoners did not die here. When their interrogations ended, they were usually driven at night to a site outside the city, near the village of Choeung Ek. Today it is often called the Killing Fields. Many visitors go to both places on the same day. Seeing the two together helps explain how the system worked, from arrest and confession to execution.

After 1979, the site opened to the public as a museum, and it has served as a place of evidence and memory ever since. Its archive of photographs, confessions and records was added to UNESCO's Memory of the World Register. In 2023, Tuol Sleng, Choeung Ek and a former prison known as M-13 were listed together as World Heritage memorial sites. The records also served as evidence at an international tribunal backed by the United Nations. In 2010, that court convicted Duch of crimes against humanity. On appeal, he received a life sentence. He died in 2020.

Only a handful of prisoners are known to have survived S-21. Most lived because the prison found them useful, for example as painters, mechanics or photographers. In past years, survivors such as Chum Mey and Bou Meng sat in these grounds, speaking with visitors and sharing their memoirs. Their presence turned history into a living conversation. You may also find exhibitions here about the guards, many of them teenagers, and about families still searching for their relatives.

It is normal to need a pause. There are benches in the shade of the trees. Many visitors sit for a while before they continue. Cambodians come here too, sometimes to look for a familiar face among the portraits. The museum asks visitors to stay quiet and to behave with respect, because for many people this is a place of mourning, not only a place of history.

Before you leave, stand once more in the courtyard. Look at the classrooms, the balconies, the trees and the white tombs. Listen to the street outside, where the city carries on with its daily life. Phnom Penh rebuilt itself around this school. As you walk back through the gate, you carry some of these faces with you. Remembering them is part of why this place is kept open.