After the end of Khmer Rouge regime, there were many documents and evidence left behind which are proof that the regime existed. Preserving the documents is very important for Cambodian citizens. These days, there are over 1 million documents related to the regime which include the confessions, conversational letters, photographs and torture equipment. These were collected from many parts of the country and one place was from S-21, the Khmer Rouge’s torture center in Phnom Penh.