Forty years ago, in August of 1975, the Communist Party of Cambodia – the Khmer Rouge – turned a high school into a death camp called S-21. The “S” stands for santebal, which is the Khmer word for “peace keeper.” During the four years that the Khmer Rouge were in power, from ’75 to ’79, 12,000 prisoners at S-21 were tortured, experimented on and murdered.In May of 1977, a Cambodian named Bou Meng was working in a Khmer Rouge “cooperative,” a forced labor camp where he and his wife were being “reeducated.” Before the Communist revolution, Bou had been a painter. He was working in a vegetable patch when some of his Rouge overseers showed up and told him that he and his wife were being transferred to a school of fine art, to teach. Once Bou and his wife had been driven outside the camp, they were bound and blindfolded, and sent to S-21. Bou had no idea why. He never saw his wife again.Vann Nath was also a Cambodian ex-painter living under the Khmer Rouge. In December of ’77, he was arrested and told he had been outed as a traitor. He was tortured with electric wires for a week, and then transferred to S-21.In 1977, Chum Mey was a Cambodian mechanic working on machinery in a clothing factory. When Party members showed up at the factory looking for him, he addressed them, respectfully, as “sirs.” He was lashed a hundred times, on the spot, for the crime of not addressing them as “brothers.” After the whipping was finished, one of the Rouge began to beat Chum with a stick. He tried to shield himself, so they broke his fingers. They attached wires to his ears, and ran the wires to electrical outlets. His eyes nearly exploded out of his head. Afterwards, he was sent to S-21.After Chum had been tortured continuously for 12 days, after his fingernails had been torn out, he confessed to being an agent of both the CIA and the KGB. He had no idea what either was, but that’s what he was told to confess. He was forced to denounce his fellow CIA and KGB officers – other random, innocent Cambodians. Chum had been arrested because someone had, under torture, denounced him; his denunciation would lead to more arrests, more torture and more denunciations. That’s how, in the course of just four years, thousands and thousands of enemy agents were sequestered in S-21. Chum, Vann and Bou are the only living survivors. There were seven survivors in total. Every other inmate of S-21, to a man, was murdered.When Vietnam invaded Cambodia in 1979, S-21’s staff fled, leaving its last seven prisoners alive – seven men whose executions had been briefly stayed to prolong their usefulness: normally, after confession, execution followed immediately. The two painters were working on a portrait of Pol Pot; Chum Mey, the mechanic, was repairing some machinery. We know about S-21’s 12,000 murdered prisoners because, in the jailers’ haste to flee, they forgot to destroy its records. In fact, S-21 is the only Khmer Rouge secret-police-prison whose records weren’t destroyed – out of a total of about 200.S-21 wasn’t just for enemy agents; it was also for their families, and for intellectuals, and the intellectuals’ families. According to a man named Suor Thi, who had been the administrator at S-21 in charge of registering new prisoners, the figure of 12,000 may be incomplete. The children didn’t make it into the archives. “I paid no attention to the children... None of the children would survive. All of them would be killed.” Of course, all the prisoners, young and old, were going to be killed – but the children didn’t have to confess first. They were just killed on principle, to tie up loose ends.Suor Thi was asked about his role registering S-21’s inmates during the trial of Kaing Guek Eav, known as Duch, pronounced “Doyk.” Duch had been the commandant of S-21. Because of his failure to destroy S-21’s records, he had the bad fortune to be one of just three Khmer Rouge tried by the international Khmer Rouge tribunal, which was established in 1997. Duch succeeded in wiping out almost all of the witnesses – only Chum, Vann and Bou were left to testify – but he was damned by his own words. A document from the S-21 archives quotes minutes from a meeting at which Duch taught his subordinates Communist Party doctrine: “Forget the idea that beating a prisoner is cruel. There’s no place for kindness in such cases. You must beat them for national, international, and class reasons.”“S-21 was only for people who were going to be executed,” said Duch at his trial, in 2009. “There was no protection of their rights. We fed them like animals and treated them as such.”Duch was unique among former Khmer Rouge in that he confessed to some of his crimes – specifically, those which were attested in S-21’s archives. Some of S-21’s records contain Duch’s hand-written instructions to his subordinates, re specific prisoners: “Did not confess. Torture him!” “Hit him in the face.” “Beat them all to death.” “Interrogate four; kill the rest.”Duch says one of his superiors – Nuon Chea, Pol Pot’s second in command – told him that a CIA agent had been found at another prison. Why had no CIA agents been found at S-21? “I spread word,” says Duch, “and suddenly the confessions contained plenty of mentions of CIA agents.” Duch claims he asked Nuon if the confessions were plausible. Nuon told him, “Comrade, you must think of the truth of the proletariat.” “The main thing,” adds Duch, ex post facto, “was that the proletarian class emerge victorious, no matter what.”If that meant collateral damage, it was fine by him. As for the children Suor Thi didn’t bother to register: Duch says he doesn’t remember how many were executed, but can confirm that one of S-21’s surviving memos calls for 160 children to be executed, in a single day. Duch himself was a father.The Khmer Rouge Tribunal sentenced Duch to 30 years in prison. When he appealed, his sentence was extended to life. The trial got some publicity, but not nearly as much as it deserved (one indispensable book has been written about it: The Master of Confessions, by Thierry Cruvellier). As of its 40th anniversary, S-21 is not well known – certainly not by the standards of Auschwitz or the Gulag Archipelago. That we’re condemned to repeat forgotten history has become so cliched a cliche that it’s almost meaningless – but S-21 was not the last of the breed. There are prisons in the People’s Republic of China where prisoners of conscience are tortured, murdered, and harvested for their organs – by the tens of thousands. There are S-21-style prisons in North Korea – the main difference is that they’re much larger: the Committee for Human Rights in North Korea estimates that the DPRK’s political prisons contain between 150,000 and 200,000 prisoners.Israel has its own (very serious) problems to worry about – but is had a responsibility to remember that death camps still exist. And that, outside of a few bleary-eyed activists, no one is doing anything about them. Forty years ago, when S-21 opened, the Cambodian genocide could still have been stopped. What slaughters blithely ignored today will we be writing about 40 years from now? Acknowledgment: Invaluable research assistance was provided by Ruth Gelernter.The author is a columnist for National Review Online.