Hundreds of people attended a ceremony on Friday at one of Cambodia's infamous killing fields to commemorate the 2.5 million deaths which took place under the communist Khmer Rouge regime.
Officials and relatives laid flowers and gave offerings on the "Day of Remembrance," once known as the "Day of Hatred," and students performed a re-enactment of Khmer Rouge soldiers torturing prisoners.
What do we know about the Khmer Rouge genocide?
Cambodia suffered through what was likely the cruelest era in its thousand-year-long history. The Khmer Rouge regime led by Pol Pot killed almost a fifth of the country's population through executions, torture and starvation from 1975 to 1979.
They carried out one of the most radical transformations of a society ever attempted in world history.
All Cambodian citizens were relocated to the countryside, required to wear black clothing and forced to work 16 hour days in rice fields.
The nightmare lasted for three years, eight months and 20 days.
Who was Pol Pot?
Pol Pot, born Saloth Sar, led the Khmer Rouge from 1963 until 1997 and served as the General Secretary of the Communist Party of Kampuchea from 1963 to 1981.
His forces took control of Cambodia on April 17, 1975, when they entered the capital, Phnom Penh. He was educated in France and was an admirer of Mao Zedong and Joseph Stalin.
Pol Pot envisioned the creation of a "new" Cambodia based on the Maoist model and wanted to establish a purely agrarian society. The aim of the Khmer Rouge was to return Cambodia to a primitive "Year Zero," in which all citizens would participate in rural work projects without any interference from the West.
What radical changes did Pol Pot introduce?
Immediately after taking control the Khmer Rouge closed all schools, abolished currency, and eliminated courts. It also closed the mail service and sealed all of Cambodia's borders.
Religion was labelled as reactionary and all religious worship was banned. Personalised clothing was seen as an extravagance.
In his summary of the aims of the Khmer Rouge, Pol Pot said: "There are no schools, faculties or universities… because we wish to do away with all vestiges of the past. There is no money, no commerce as the state takes care of provisioning all its citizens… We evacuated the cities… the countryside should be the focus of attention of our revolution and the people will decide the fate of the cities."
The regime forced Cambodians nationwide to leave their hometowns and ordered them to march towards villages. All people, including those who were ill, disabled, old and young, that were unable to make the journey to the collectivised farms and labour camps were killed immediately. Those who refused to leave were also killed.
Suspected opponents of the new regime were eliminated and all political and civil rights were abolished. Children and parents were separated and sent to different labour camps.
The Khmer Rouge regime arrested and often executed people suspected of having connections with the former government or with foreign governments. Professionals including doctors, teachers and those viewed as intellectuals were specifically targeted.
Ethnic Vietnamese, ethnic Thai, ethnic Chinese, ethnic Cham, Cambodian Christians and Buddhist monks were targets of persecution, however, the majority of prisoners were young ethnic male Cambodians. It is believed that close to 10 percent of prisoners were women and children.
Those who survived the long and tiring marches became unpaid labourers, working on minimum rations for endless hours. They were forced to live in public communes, similar to military barracks, with constant food shortages and rampant disease.
Many Cambodians became incapable of performing physical work due to conditions of virtual slave labour, starvation, physical injury, and illness. Those who could no longer work were killed by the Khmer Rouge without mercy.
A high ranking official of the regime, Kang Kek Iew, once said: "To spare you is no profit, to destroy you is no loss."
How many people were killed?
It is estimated that between 1.5 and 3 million Cambodians lost their lives at the hands of the Khmer Rouge. On July 25, 1983, the Research Committee on Pol Pot’s Genocidal Regime issued its final report, including detailed province-by-province data. The data indicated that the number of deaths was 3,314,768, meaning Cambodia may have lost up to 25 percent of its population during just four years.
Aftershocks of the genocide
The Khmer Rouge lost control of most of Cambodia when Vietnam invaded the country in 1979. However, the people of Cambodia continued to suffer greatly.
Thousands of people fled to Thailand and were forced to eat whatever they could find, including leaves, roots, and bugs. Many died of starvation en route, or accidentally stepped on land mines laid by Khmer Rouge soldiers along the western border to prevent them from fleeing.
Often survivors of the period developed post-traumatic stress disorder. However, until the 1990s, the disorder was not recognised in Cambodia and victims weren't able to get treatment, meaning they suffered in silence.
Anything out of the ordinary can cause sufferers of PTSD to panic. For older people with heart trouble, this can trigger heart attacks.
Human rights groups estimate that about 650,000 people died in the year following the fall of the Khmer Rouge.
Justice delayed is justice denied
Bringing the perpetrators of the genocide to justice proved to be a very difficult task. It took almost 24 years for the Cambodian Government to request for help from the United Nations in prosecuting Khmer Rouge leaders.
Initially, the UN wanted to create a court similar to the International Criminal Tribunal for the Former Yugoslavia, but the government resisted its establishment because it opposed Western influence in the prosecutions.
Finally, after much negotiation, the Extraordinary Chambers in the Courts of Cambodia were established after the government agreed to an amended bilateral agreement on June 6, 2003.
Many members of the Khmer Rouge had already died before the trials began. These include Pol Pot; Son Sen – the defence minister responsible for the Santebal, the political police; former minister Yun Yat, former minister Thiounn Thioeunn, Ta Mok –Chief of Military Command; and his deputy Ke Pauk.
Many suspected perpetrators were either killed in the military struggle with Vietnam or eliminated by the Khmer Rouge itself after they came to be seen as internal threats.
Pol Pot was never brought to justice
Freelance journalist Nate Thayer interviewed Pol Pot on April 15, 1998. During the interview he said that he had a clear conscience. He denied being responsible for the genocide, asserting that he "came to carry out the struggle, not to kill people."
He died in his jungle hideout in 1998 without ever being brought to trial.
Five disturbing facts about the Cambodian genocide
1. Up to 25 percent of the Cambodian population was killed
It has proven very difficult to obtain a full and accurate count of the people who were killed by the Khmer Rouge during their time in power. The figures range from 750,000 to 3,000,000.
2. Only five people have been brought to justice for genocide crimes
Only five Khmer Rouge leaders have been prosecuted in court. Of these, the most notorious was Kang Kek Iew (known as Comrade Duch) who ran the infamous prison S-21. Cambodia refused to permit the establishment of a Yugoslav-style international war crimes tribunal. Because the court was not established until 2003, many of the accused – including Pol Pot – evaded justice.
3. The Khmer Rouge used plastic bags as a means of torture
The Khmer Rouge introduced a number of cheap yet horribly effective methods of torturing prisoners. Guards used a technique known "The Dry Submarine" which involved suffocating victims with plastic bags until they were nearly unconscious before reviving them and repeating the process.
4. S-21 was originally a high school
S-21, one of the most notorious torture and interrogation centres used by the Khmer Rouge, was originally a high school. It was established in a converted school building in the outskirts of Phnom Penh. The classrooms were turned into prison cells, some designed to be communal cells where prisoners were shackled to iron bars.
5. Year Zero
April 17, 1975, was the beginning of Year Zero. Pol Pot idolised the pre-industrial agrarian way of life and wanted to create a traditional society free from modern influence. Following the victory of the Khmer Rouge in 1975, he began to impose this vision in Cambodia. The Khmer Rouge called it "Year Zero."
Glimpses of Khmer Rouge regime atrocities