It’s hard to know exactly how far-reaching the experiments were or who knew about them (even some of the researchers involved had no idea they were participating in a government-funded project), but the transcript of the 1977 Select Committee on Intelligence is a fascinating read – and not only for the reference to the MKUltra subproject that studied “magicians’ arts as applied to covert operations.” Researchers tried to see if hallucinogens had the power to control minds, erase memories and even work as truth serum. Of particular interest to the government were the drugs that could be used to extract sensitive information, especially LSD. It’s enough to paint a terrifying picture of a wide-ranging government project that sought to capitalize on mind-control techniques that could, theoretically, be used against enemies during the Cold War.

Most of the documents relating to the project were destroyed by the CIA in 1973 because of course they were, but what we know comes from witness testimony, a couple congressional investigations and a cache of 20,000 incorrectly-filed budgetary documents found during a Freedom of Information Act request in 1977. It tested countless subjects at over 80 institutions, many of which were fronts funded by the government and filtered to schools, private hospitals and even a couple jails. When Chief Hopper tracks down Terry Ives, the woman who attempted to sue the government for abuse after what happened to her at Hawkins, he and Ives’ sister talk about “Project MKUltra.” Though it sounds like what conspiracy theorists’ wet dreams are made of, MKUltra was a real government program funded by the CIA that went on from the 1950s to the early 1970s. Obviously spoilers abound, so come back later if you’re not done with the show yet. But which elements are more fact than fiction? Here are five examples from the show that had real-life equivalents – some of them freaky enough to make monsters look like an appealing alternative.

Secret government programs