Situated about 17 km south of Phnom Penh, Choeung Ek Memorial has been known as the site of a former orchard and large-scale grave of Khmer Rouge. Among many other well-known locations in Phnom Penh in particular and Cambodia in general, this memorial is considered the best-known with the name The Killing Fields, where the Khmer Rouge dynasty executed over one million people between 1975 and 1979.

This place witnessed the dreadful scene during the period of 1975 and 1978, when around 17,000 men, women, children and infants (including 9 Westerners) was detained and tortured at S-21 prison (now Tuol Sleng Museum).  They had to wait here for 24 hours before they were wiped out in order to save valuable bullets by a blow to the head after which their throats were slit. In nearly the same way, babies were killed by being bashed their heads against a tree. The remains, many of whom were bound and blindfolded, were disinterred in 1980 from mass graves and 43 of the 129 communal graves here have been left untouched. These graves are categorized and placed separately for men, for women and for children. When exhuming these graves, people found over 8000 skulls, arranged by sex behind the clear glass panels of the Memoral Stupa.

Throughout the country of Cambodia, there were many killing fields, but Cheung Ek was believed to be the largest one. Annually, on the 20th of May, a ceremony is held around the stupa with the hope to bring peace to the spirits of both the dead and the living. Cheung Ek Killing Field in Phnom Penh is a very important place in the city as it has a long history attached to it. In addition, it is really fascinating for all those coming to visit the city, attracting a number of internal and external tourists to visit. Even the Government always encourages the residents to come to take a look because the place has a long history behind it and reminds one of the horrifying times that the people of Cambodia have gone through during the reign of Khmer and after.