Cambodian World Heritage Site
As of July 2025, UNESCO has inscribed a 5th Cambodian World Heritage Site to their list with the creation of a Cambodian Memorial Sites entry. The listing combines three separate sites: Choeung Ek – more commonly known to visitors as the Killing Fields, Tuol Sleng or S21 – the Genocide Museum, plus a third site simply named M-13. The former is situated in the southern suburbs of Cambodia’s capital, Phnom Penh, the second is close to the city centre, while M-13 is, we believe, a former prison and mass burial site located in Kampong Chhnang Province to the northwest of Phnom Penh. (We’ve never visited the latter and UNESCO’s inscription is so recent that their corresponding website page doesn’t even feature a description yet.)
Existing Cambodian UNESCO listings are Angkor (1992), Preah Vihear (2008), the Temple Zone of Sambor Prei Kuk (2017) and Koh Ker Ancient City (2023).
Choeung Ek and Tuol Sleng are a predictable addition to the Cambodian World Heritage Site list, and while it is of course a very grim heritage, it is tragically world heritage and of vital historical importance. (We wonder if the irony of adding a genocide museum to a World Heritage List while genocide is taking place in another part of the World as we write escapes UNESCO or not.)
Tuol Sleng – formerly a lycee, prison and now a museum For those who haven’t yet visited Phnom Penh, we’d say do so as soon as possible, and here’s a brief rundown on the two sites for those who aren’t familiar with them. Tuol Sleng or S21, situated just south of Phnom Penh’s centre, close to the Russian Market, was a former lycee converted into a prison and interrogation centre during the Khmer Rouge period from 1975 to early 1979. The site was established as a museum in 1980 by the Vietnamese-backed government of Kampuchea, with the four former school blocks (A, B, C and D), and the grounds remaining pretty much as the Vietnamese soldiers found them when they liberated the site. A notorious wall map of Cambodia made of human skulls has since been removed, while attempts were made to remove the blood stains on the floor. Today, the ground floors of A, B and C are more or less as they were in 1979, while the upper floors and block D now house exhibitions and photo displays.
As we said, pretty much as it was found in 1979. (The blood stains were scrubbed off a few years ago) As the name S21 suggests, this was just one of many such sites in the capital, while the KR also established similar prisons in every regional city and town of any size across the country. Equally, the famous Killing Fields site at Choeung Ek was also one of many. Prisoners from S21 were transported to Choeung Ek for execution and burial in mass graves.
Local kids at Choeung Ek, the Killing Fields Note that, distressing as they are, both museums are extremely informative and help to explain many facets of Cambodia, its people and society today, so while we do have guests requesting alternatives to the visits, we do recommend going. Clearly, in the case of our Cambodia family tours, the two sites are not appropriate for younger kids, so again, alternatives are offered.
Both sites appear on all our Cambodia tours featuring Phnom Penh as well as the Cambodia and Vietnam Overland tour and the Cambodia and Laos Indochina Adventure.
