Day of Remembrance is celebrated annually on 20 May at Choeung Ek Killing Fields. Today, the Cambodian government celebrated this ceremony at the same site—Choeung EK—where prisoners were brought from the S-21 security office to be killed. Located about 15 kilometers from S-21, Choeung Ek was home to a group of about ten young men led by Teng, whose responsibility was to execute all prisoners being sent from the S-21 security office during the time of Democratic Kampuchea. Prisoners were brought into Choeung Ek by trucks every single night from S-21. Upon being informed that prisoners were brought in, Teng and his team dug the graves to be ready. Teng and his team killed the prisoners and then buried them in the graves.

Like other areas across the country, "Day of Remembrance" was celebrated at the former killing sites where Khmer Rouge executed people or committed other crimes.

In today’s ceremony at Choeung Ek, a reenactment of life during the Khmer Rouge regime was performed to show the atrocities committed by the Khmer Rouge during Democratic Kampuchea, who ruled the country for a period of three years, eight months and twenty days between April 17, 1975 and January 6, 1979.