While most horror movies have in some way taken inspiration from or explore classic tales of supernatural monsters or other real-world phenomena, there is also a select genre of horror films that are able to strike fear into viewer's hearts with just a few simple words; "based on a true story."
While that isn't exactly a promise that the film carrying that tagline is absolutely true, that smallest shred of realism offers a new layer of terror for fans looking to escape to a horror movie because what happened on the screen could now conceivably also happen to them. The new millennium saw quite a few horror films with this tagline that we'll look at today.
From Hell (2001)
2001's From Hell is a loose adaptation of the graphic novel of the same name from Alan Moore and Eddie Campbell that takes place during London's Whitechapel Murders that became attributed to Jack the Ripper.
The film follows the investigation of Johnny Depp's Inspector Abberline as he uncovers a royal conspiracy that has a dark connection to the ongoing murders of sex workers that caught the attention of the world due to the unsolved mystery of the man behind the murders who claimed to be "from Hell."
The Mothman Prophecies (2002)
Richard Gere and Laura Linney starred in 2002's The Mothman Prophecies, which takes place in the town of Point Pleasant, West Virginia where a number of real-world sightings of a mysterious creature known as the Mothman were reported.
The film posits that the Mothman sightings were part of a prophetic warning shared with Gere's character about the impending collapse of the Silver Bridge that claimed a number of lives, and while the real bridge collapse was explainable, the truth behind the Mothman sightings remains a mystery.
Open Water (2003)
2003's Open Water touched on a number of fears even before it added the "based on a true story" tag, as it followed a couple on a scuba-diving expedition off the reefs of Australia who are left behind by their boat as they struggle to survive sharks and the elements.
The film was based on the real-life disappearance of Tom and Eileen Lonergan, who were similarly abandoned by their dive boat without notice for two days before a search was sent out, though nothing but items of clothing and some of the diving equipment was found.
An American Haunting (2005)
The legend of the Bell Witch began as a series of ghostly encounters that afflicted the Bell Family in 19th-century Tennessee that escalated from visitations to attacks and eventually led to the poisoning of the family's patriarch.
2005's An American Haunting reexamined the haunting of the Bell family by a witch-like spirit while also exploring a similar haunting in the modern-day, which are both revealed to be warnings and retribution for sexual molestations by the fathers of each family.
The Amityville Horror (2005)
2005's remake of The Amityville Horror was based on the book of the same name, which itself was based on the story of the Lutz family, who had abandoned their new home claiming it was possessed by demonic spirits.
The real house was the actual location of the 1974 murders of the DeFeo family which further led claim to the story, though the remake explored the supernatural elements of the Amityville haunting in a new way that the real George Lutz took issues with, leading to a lawsuit.
Wolf Creek (2005)
2005's Wolf Creek follows a group of backpackers in the Australian Outback who are targeted and attacked by a psychopathic killer with a mad-on for tourists played by John Jarratt, who would reprise the role for the sequel and web-series.
While the film claimed to be "based on true events," the character of Mick Taylor was actually created as an amalgamation of other Australian killers like Ivan Milat and Bradley Murdoch who served as inspiration for the film.
The Exorcism Of Emily Rose (2005)
Scott Derrickson co-wrote and directed 2005's The Exorcism of Emily Rose, which explored the legal case of a priest charged with negligent homicide after he performed an exorcism on the titular Rose, which ultimately resulted in her death.
The film was loosely based on Anneliese Michel, a young girl whose family enlisted the aid of the Catholic Church after years of medication failed to help their epileptic daughter, though she later died after over 60 exorcism sessions that led to charges against the priests and the parents.
Borderland (2007)
2007's Borderland featured a group of American college kids in a Mexican border city who encounter a sadistic cult led by a serial killer after one of their friends was kidnapped off the streets to be used as a ritualistic sacrifice.
While the premise sounds like it was made for a movie, it was loosely based on Adolfo de Jesús Constanzo and his Narco-Satanists (they were also drug smugglers involved with the cartels) and their murder of an American student in 1989 at the cult's terrifying ranch.
Zodiac (2007)
David Fincher's 2007 Zodiac explored the unsolved murders and public fascination with the real-world Zodiac Killer, who shot and killed couples in cars before escalating into a costumed killer who taunted the police and reporters.
Zodiac was based on the book of the same name by Robert Graysmith, who is played by Jake Gyllenhaal in the film. Graysmith's investigation and personal connection to the crime along with the unknown identity of the Zodiac layers the film with tense moments as San Francisco dealt with one of the most infamous killers of the 21st century.
The Haunting In Connecticut (2009)
2009's The Haunting of Connecticut claimed to be "based on true events," though there was some controversy regarding its legitimacy, as the author of the original book revealed he had been directed to embellish accounts by famed demonologist Ed Warren.
The film followed the Campbell's as they moved into a new house with a hidden mortuary in the basement that may have been used for dark rituals, which led to the possession of the family's young child as trapped spirits attempted to use his body to break free from the house.