When people think about horror films, they don't usually presume those horrors have any basis in reality. Especially if they work with supernatural elements, such as demons or ghosts. However, that's not always the case. History has its fair share of noted strange events and people haunted by scary forces.
It makes sense for horror films to draw inspiration from them since what's real is often the most terrifying thing. Horror films also often made use of the stories of murderers whose crimes were often just as frightening as the work of any ghost, if not more.
10 The Exorcist (1973)
When The Exorcist came out, it was a controversial film for many viewers thanks to its open portrayal of exorcism. However, some of the audience might have been even more shocked if they had known the film was based on a book inspired by real events. Instead of a girl named Linda, it was a boy named Roland Doe who was supposedly possessed by demons in 1949.
It happened after his aunt had died. The boy's family was hearing strange noises and saw furniture move or things fly through the air in Roland's presence. The exorcism process turned out to be so frightening that the people who witnessed it felt compelled to capture their experiences in a literary form.
9 Psycho (1960)
Alfred Hitchcock is best known as a horror director nowadays even though he mostly directed thrillers. Psycho is his most famous horror film. Based on a book by Robert Bloch, the story drew inspiration from real-life crimes committed by the infamous Ed Gein.
Gein was a Wisconsin killer who was convicted for a single murder but might have been responsible for others. He also was a grave robber and decorated his home with skulls and such. Norman Bates, the main villain of Psycho, had no such decorations in his home but his unstable nature made him just as dangerous.
8 The Conjuring (2014)
Most people hold traditional jobs and can't imagine what it would be like to work as ghost and demon experts. Ed and Lorraine Warren did exactly that. In the first film inspired by their work, Ed and Lorraine tried to save a family from evil spirits. The story happened in 1971 when the Perron family moved into a farmhouse in Rhode Island.
They started hearing strange sounds and saw spirits in the house. The family ended up living in the same house until 1980. Ed and Lorraine visited them multiple times to investigate what was happening but Roger Perron, the father of the family, asked them to leave after they had performed a séance in the house. As far as horror films go, The Conjuring has a strong basis in reality even when it comes to its villains. It not only draws inspiration from real events but also introduces the heroes who witnessed them.
7 The Conjuring 2 (2017)
The unfortunate family's case wasn't the only mystery the Warrens had ever investigated. The Conjuring 2 captured another case of theirs. This time, they were helping a single mom and her children in whose house strange things were happening.
The real story happened in the 1970s in London in Peggy Hodgson's family. It started with strange noises and continued with the presumed presence of a poltergeist. Ed and Lorraine visited the family but weren't able to solve the problem.
6 A Nightmare On Elm Street
Just like with any horror film with a strong supernatural element, it's hard to imagine that these plots could be based on real events. A Nightmare on Elm Street introduced the terrifying concept of a murderer Freddy entering young people's dreams.
According to the director, he came up with the story's idea after he had read an article about a young immigrant boy who faced horrible nightmares after coming to America from Cambodia. The boy said that if he fell asleep, the things chasing him would kill him in his dream. He indeed died in his sleep in the end, just like many characters in the film succumbed to their nightmares.
5 Child's Play
Just like A Nightmare on Elm Street, Child's Play is an undeniable classic of the 1980s. All horror fans know the story - a doll turns out to host the soul of a serial killer who once again starts killing. Not everybody knows that such a doll existed and was said to have been possessed by evil spirits.
The writer and painter Robert Eugene Otto had the doll as a child. According to his parents, young Otto would talk to the doll and the doll would answer back. They also claimed the doll was able to run from one room to another. While it's never been explained what was happening with the doll, the film offered its own interpretation of the sinister events.
4 Poltergeist (1982)
The 1980s saw the creation of more than one horror film that has become iconic since. Poltergeist tells the story of a family haunted by the titular ghost. In the end, the poltergeist kidnaps the parents' youngest daughter. The story has a base in reality to a certain degree.
In 1958, a family from New York experienced furniture moving, bottles exploding and other strange things happening in their home. Luckily for the family, it all stopped after just two months. As all horror fans will know, things inexplicably moving are the typical clues to a poltergeist's presence.
3 Birds (1963)
Psycho isn't the only iconic horror film of Alfred Hitchcock's. In this film, birds start attacking people seemingly out of no reason. Something similarly frightening, albeit less drastic supposedly happened in California in 1961.
A flock of birds in Monterey Bay started ramming into people's homes and scared them. It's unclear what caused the birds' behavior. Just like the film didn't give any explanation of what had happened to make the birds act like this. That made the situation all more desperate since the heroes had very few ideas about what to do.
2 10 Rillington Place (1971)
Horror films about murderers often have their basis in reality. The reason is they don't have to contain any supernatural elements to be frightening. This classic British crime horror film portrays the actions of the serial killer John Christie.
Christie's neighbor Timothy Evans was later accused of Christie's actions. It's known that Christie killed at least eight women (his wife included) but the total number of his victims could have been higher. And as for the film's somewhat cryptic title, 10 Rillington Place was Christie's home and also the place of the murders.
1 Zodiac (2007)
Before they acted together in the MCU, Robert Downey Jr. and Mark Ruffalo as well as Jake Gyllenhaal met in the movie portraying the decades-long case of the serial killer Zodiac. Unlike the above-mentioned John Christie, the investigators have never found out who Zodiac was.
All they know was that he was killing people in the late 1960s and early 1970s. The film balances between thriller, drama, and horror, depending on whether it portrays the crimes themselves or the desperate investigation.