5. The Silence of the Lambs (1990)
The horror movie: An Oscar-winning horror-thriller in which FBI trainee Clarice Starling (Jodie Foster) is chucked in at the deep end when she's tasked with working alongside cannibal Dr. Lecter (Anthony Hopkins) to bring down Buffalo Bill (Ted Levine).
The true story: Author Thomas Harris based Buffalo Bill on a number of serial killers, including Ed Gein (skinning his victims) and Ted Bundy (using a cast to lure in innocent women). Harris also based the relationship between Starling and Lecter on that between Bundy and Robert Keppel, a criminal profiler and professor at the University of Washington.
4. Psycho (1960)
The horror movie: A Hitchcock classic starring Janet Leigh as the runaway employee who's just ripped off her boss. Karma intervenes when she lands at the Bates Motel, where she comes to a sticky end in one of cinema's finest shock scenes.
The true story: Robert Bloch based his novel very loosely on Ed Gein, the serial killer who murdered women in Wisconsin. Bloch didn't use Gein as a template for his story, though. He started writing his novel at the time Gein was arrested. When the story hit the news, it sparked Bloch's imagination.
3. The Exorcist (1973)
The horror movie: The exorcism movie to end all exorcism movies. Based on William Peter Blatty's novel, William Friedkin directs Linda Blair as the young girl who unleashes demonic forces with a Ouija board... and soon finds herself possessed by the devil himself.
The true story: Blatty's book was itself inspired by the case of Roland Doe, the pseudonym given to a boy who was allegedly possessed in 1949. The Catholic Church was brought in to perform an exorcism. In the years since, the general consensus is that Doe suffered from an extreme, undiagnosed mental illness.
2. Jaws (1975)
The horror movie: The first official blockbuster, though it doesn't resemble any of the massive-budget blockbusters that contemporary cinema-goers are accustomed to. Based on Peter Benchley's novel, Steven Spielberg's film follows police chief Martin Brody (Roy Scheider) as his beachside town is attacked by a great white shark.
The true story: Benchley's book was inspired by the story of fisherman Frank Mundus, who caught a great white shark in Long Island in 1964. Other writers also claim that Benchley drew inspiration from a spate of shark attacks in Jersey Shore in 1916.
1. The Texas Chain Saw Massacre (1974)
The horror movie: Genre-defining horror slasher in which a group of teenagers fall prey to a chain saw-wielding maniac called Leatherface. There have been numerous sequels and remakes, none of which come close to Tobe Hooper's powerful and gritty original.
The true story: Though the film's plot is fictional, the character of Leatherface is partly based on real-life serial killer Ed Gein, who was found in possession of nine 'human skin' masks when he was arrested.