A new documentary, Room 237, explores the theory that messages are hidden in horror film The Shining. So what meanings do some people believe its director Stanley Kubrick secreted in the frames of his chilling masterpiece?
Kubrick's adaption of the 1977 Stephen King novel of the same name was released in cinemas 32 years ago.
The film follows recovering alcoholic and struggling writer Jack Torrance, played by Jack Nicholson, and his wife and their young son Danny.
They move into the Overlook Hotel after Jack is appointed caretaker of the imposing and isolated North American mountain retreat while it is closed for winter.
Tension mounts as Danny, who has psychic abilities, and his troubled and abusive father encounter the evil spirits that haunt the Overlook's deserted corridors and its sinister room 237.
In an interview with French film critic Michel Ciment, Kubrick said he hoped audiences would get a "good fright" watching it.
But some viewers believe The Shining is far more than a scary film.
They are convinced the characters' dialogue, their clothing and even the pattern of the Overlook's carpet are codes. Breaking those cryptic clues, they argue, reveals hidden messages about the genocide of America's indigenous people, the Nazi's Final Solution and even an admission the 1969 Moon Landing was faked.
Filmmakers and best friends Rodney Ascher and Tim Kirk, who are both huge fans of Kubrick's work, explore these theories and others in their documentary Room 237.
Ascher said: "I wasn't looking for messages myself.
"This project began because my friend Tim and I discovered that countless other people were doing so, and based on our love of Kubrick's films, and consciousness of the great lengths he went to make them, the idea that The Shining was littered with these signs and symbols was totally plausible to us and something we wanted to know everything about."
He added: "As I discovered more and more of them, it actually became a little frightening, as if I was opening up a book of forbidden knowledge - doing most of the research between the hours of 10pm and 3am made the experience especially eerie."
Room 237's interviewees include Michigan-based history professor Geoffrey Cocks, who believes The Shining is about Nazi Germany's extermination of Jewish people.
Prof Cocks, who wrote the book The Wolf at the Door: Stanley Kubrick, History and the Holocaust, points to repeated use of the number 42 in the film. Danny wears a baseball shirt with the number on the sleeves, and another scene a TV set shows the movie Summer of '42.
In 1942, Nazi officials met for the Wannsee Conference to plan the genocide of European Jews.
Other clues to the Holocaust theory include Kubrick changing the colour of the Torrance family's VW Beetle from the King novel's red to yellow - the colour of the star-shaped identification badges Jews were forced to wear.
Another interviewee, veteran US television journalist and former war correspondent Bill Blakemore, suggests The Shining is about the mistreatment of America's Native Indians.
Blakemore's evidence includes an explanation early on in the film that the Overlook was built in 1907 on an Indian burial ground. In 1907 the name Indian Territory, an area of land where the US government relocated North American indigenous people, changed to Oklahoma.
Later in the film, a frustrated Jack bounces a rubber ball off an Indian tapestry that hangs on a lobby wall. Meanwhile, in the hotel's larder are stocked tins of baking powder branded Calumet, the word for an Indian peace pipe.
One of the more startling theories is that The Shining is Kubrick's confession to helping the US government fake the Apollo 11 Moon Landing.
Author and film-maker Jay Weidner insists the signs are all there.
In one scene, Danny is playing with toy cars on the hotel's oddly patterned carpet. He sits inside a hexagonal shape - the same shape, says Weidner, as the launch pad area of Apollo 11. When Danny rises from his game, a rocket with the lettering Apollo 11 on it can be seen on the boy's jumper and he walks slowly towards room 237. According to Weidner, schoolchildren in the 1960s were taught that the distance from the Earth to the Moon was 237,000 miles.
Critic Ciment asked Kubrick why he switched the hotel room number from the book's 217 to 237. The director said the Timberline Lodge, in Oregon, which was used for the film, had a room 217 but staff feared no-one would want to stay in it after the film was released, so it was decided to change it to 237, a room number that did not exist in the lodge.
Matthew Leyland, reviews editor at Total Film magazine, is not surprised that people continue to be captivated by The Shining so long after it was released.
He said: "It's a scary film that still scares.
"Horror films can sometimes date terribly but apart from the bell bottoms and the odd hammy moment, Kubrick's film holds up incredibly well after 30-odd years.
"Most of his films - particularly the later ones - have a persistent sense of foreboding, of something truly ghastly about to happen, but this is Kubrick at his eeriest and most uncanny."
Leyland said Kubrick was fond of symbolism and cryptic vibes. He said the imagery and themes in his most famous film, 2001: A Space Odyssey, have invited endless speculation and interpretation over the years.
He added: "Given what a meticulous, painstaking, serious-minded director Kubrick was, it's probably likely that he intended The Shining to be more than just a story of a man going mad in a hotel, although I thought many of the theories espoused in Room 237 were more entertaining than credible."
After watching Room 237, Leyland reckons most viewers of The Shining will see it in a different light than they had in previous viewings.
For Ascher, the documentary's director, delving into the theories left him with some concerns about how he might feel when watching The Shining again.
He said: "I had a fear that in a way, by deconstructing the film, I may have killed this thing I loved.
"But happily enough, when I recently re-watched the film about a month ago with my mother-in-law who was preparing to watch 237, I was instantly able to fall under its spell again."
Room 237 is released in the UK on 26 October.