Cambodia\'s recent history
Tuol Sleng and Choeung Ek
By SmileJet Editorial Team · Updated May 2026
These are memorial sites, not tourist attractions. They document the Khmer Rouge regime\'s genocide against the Cambodian people from 1975 to 1979. We have written this page so that visitors arrive informed, prepared, and able to engage with appropriate respect.
A note on framing before we begin
This page does not appear in our things-to-do listings the way the Royal Palace or the Mekong cruise do. It is not a "must-see Phnom Penh attraction." It is information for visitors who feel they want to engage with Cambodia\'s recent history while in Phnom Penh, and who want to do so well.
You are not obligated to visit these sites. Many SmileJet patients choose not to, and that is a perfectly reasonable choice. A trip to Cambodia is not incomplete without them. If you do go, what follows is intended to help you arrive ready.
Historical context
Between April 1975 and January 1979, the Khmer Rouge regime, led by Pol Pot, controlled Cambodia. They evacuated cities, abolished currency and private property, and pursued an extreme agrarian-utopian ideology that targeted the educated, the urban, religious and ethnic minorities, and ultimately anyone perceived as a threat to the regime. An estimated 1.7 to 2 million Cambodians died from execution, starvation, forced labour, and disease — roughly a quarter of the country\'s population at the time.
Tuol Sleng (Security Prison 21, or S-21): A converted high school in central Phnom Penh that served as the regime\'s most notorious interrogation centre. An estimated 14,000 to 20,000 people were imprisoned and tortured here. Almost no-one survived. The site was preserved largely as it was found in 1979 — bare cells, photographs of the imprisoned, the implements of interrogation. Today it functions as a museum of remembrance.
Choeung Ek: One of many "killing fields" across the country, located 17km southwest of Phnom Penh. Prisoners taken from S-21 were transported here for execution. Approximately 8,895 sets of human remains were exhumed from the mass graves at Choeung Ek; many graves remain undisturbed. A Buddhist memorial stupa now stands at the site, containing the skulls of those exhumed.
The Khmer Rouge regime was overthrown by Vietnamese forces in January 1979, after a series of border conflicts. The transition out of Khmer Rouge rule was difficult and protracted; modern Cambodia\'s political and social fabric continues to engage with this history in ways that visitors should approach with humility.
What to expect, emotionally
Both sites are difficult. Tuol Sleng presents the photographs of those who were imprisoned, taken at the moment of their arrival at S-21 — galleries of faces, mostly young, mostly bewildered. Choeung Ek includes the stupa with skulls visible behind glass, a "killing tree" identified for its specific use against children, and walking paths through ground where graves remain.
Most visitors describe the experience as quietly devastating rather than dramatically distressing. Some find the physical proximity to the events more moving than they expected. Some find the audio guide narration — which often features survivors and the relatives of victims — more affecting than the physical sites themselves.
If you carry significant trauma history of your own, or if you are recovering from major surgery and your emotional reserves are low, we suggest postponing the visit to a different trip rather than attempting it during recovery. These sites do not improve with rushed visits.
Practical guidance
When in your trip: Day 4 or later, if at all. Earlier in recovery the physical and emotional demands are too much. The Royal Palace and National Museum are better-suited to days 2 and 3.
Combined visit: Most visitors do both sites in a single day with a tuk-tuk or Grab driver who waits between them. Tuol Sleng in the morning (when the light is gentler), Choeung Ek after lunch. Allow the full day; do not pair this with other activities.
Audio guides: Highly recommended at both sites (US$3 to US$5). The narration is restrained, factual, and includes survivor voices. Without it, the visit can feel context-poor. With it, the sites become coherent.
Dress: Modest dress is appropriate. Cover shoulders. Long pants or skirts. Subdued colours. These are not casual tourist sites.
Photography: Permitted at both sites but please consider whether each photograph is genuinely intended for personal record or reflection, not for social media. Many visitors choose not to photograph the interior galleries at Tuol Sleng, particularly the photographs of the imprisoned. There is no requirement to photograph anything. Selfies and "Instagrammable" framing are deeply inappropriate.
Behaviour: Speak quietly. Do not eat or drink in the galleries. Do not laugh, joke, or pose. Other visitors may be Cambodian — many have direct family connections to those who died.
Children: Both sites contain graphic content (photographs, human remains). They are not appropriate for young children. Older teens may engage meaningfully if they have prior context; brief them before you arrive.
If a SmileJet coordinator visit is helpful: Your coordinator can arrange a Khmer-speaking guided visit at SmileJet partner rates. The guides we work with are trained at the cooperating museum and provide context with care. Mention this in your quote form if interested.
Modern Cambodia is more than this period
Cambodia\'s history is vast — at least 2,000 years documented, with the Khmer Empire of Angkor (9th to 15th century) being one of the great civilisations of pre-modern Asia. The Khmer Rouge years, however devastating, are 4 years out of millennia. Visiting Tuol Sleng and Choeung Ek without also engaging with the rest of Cambodia\'s story produces a distorted picture.
If you have the time, visit the National Museum of Cambodia (Khmer Empire art and sculpture) and the Angkor Wat temple complex via Siem Reap. Read about the contemporary cultural revival in dance, film, and literature. Speak with Cambodian people, who carry the history without being defined by it.
The visit to Tuol Sleng and Choeung Ek, done well, sits within a fuller engagement with the country, not above it.
Plan your Phnom Penh trip
Mention any particular site visits in your quote form and your coordinator will fit them into your treatment timeline appropriately.
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