Pitești Experiment in Romania overseen by the Soviet Union. Probably the worst thing that humans have ever done to other humans. Makes Unit 731 look like daycare. Communist Russia was probably the most evil human organization to ever exist.
It was basically an experiment to prove souls dont exist. That any human, no matter how resilient, can be broken or "demasked" into an animal like slave. and they prove this by killing the human spirit with 24/7 torture, degradation, brainwashing and humiliation. besides the obvious brutal violence stuff like eating your own s**t, vomit, and forced to desecrate every sacred belief you ever held until you totally broke. and they did this to the most resilient anti communist student activists. and they all broke. then they forced them to be the torturers for their fellow comrades. with the threat that if any of the tortured admitted that they were the guard that shown them a shred of mercy or leniency, they would be sent back to the beginning of the program to experience it all again which most did several times. if these prisoners were given even the slightest chance they instantly tried to commit suicide. some even chewed through their wrists to get to their veins. which the communists solved for by knocking out all of their teeth
One of the biggest mistakes the western world made was not make the crimes of the Soviet Union more known. Everyone should know this happened, that yes there was an organization of people much worse than even the Nazis.