1. Tom Selleck was originally cast as Indiana Jones.
2. James Cameron wanted Gwyneth Paltrow to play Rose in Titanic before Kate Winslet ended up playing the part.
3. Another re-cast: Leonardo DiCaprio was hired to play maniac Patrick Bateman in American Psycho but eventually walked, leaving way for Christian Bale.
4. Once in the role, Christian Bale based some of his performance on Tom Cruise because he watched an interview of the actor and saw "this very intense friendliness with nothing behind the eyes."
5. All of the clocks in the pawn shop in Pulp Fiction are set to "4:20".
6. Instead of CGI, Tim Burton got 40 squirrels trained up to crack nuts for Charlie & The Chocolate Factory.
7. Director James Cameron is actually the one sketching Kate Winslet nude in Titanic.
8. Ridley Scott vetoed Louise kissing Thelma at the end of Thelma and Louise, but Susan Sarandon did it anyway without his say-so. Scott had no choice but to use the take, as it was the last shot on the last day of filming.
9. The sounds made by the brachiosaurus in Jurassic Park were a combination of whale and donkey sounds.
10. The phrase "old sport" is said 55 times during The Great Gatsby.
11. Pumbaa in The Lion King was the first character to fart in a Disney movie.
12. On that note, the line-up in The Usual Suspects was originally meant to be serious, but Benicio del Toro couldn't stop farting, so the cast were shown laughing instead.
13. In every scene where someone dies in The Departed, there is a visual "X" on screen right before the death.
14. Joe Pesci ACTUALLY bit Macaulay Culkin's finger in Home Alone when Harry bites Kevin, and the actor still has a scar to this day.
15. In Drive, when Ron Perlman is beaten up on the beach, his screams of pain are real, as he actually shattered his kneecap during the scene.
16. A 13-year-old Lily Allen is in Elizabeth alongside Cate Blanchett.
17. Eric Stoltz was originally cast in Back to the Future as Marty McFly — and even filmed half of the movie — before he was given the boot for Michael J. Fox.
18. Star Wars began life called The Star Wars, but "the" was dropped fairly early on.
19. There's only a 12-year age gap between father-son duo Sean Connery and Harrison Ford in the Indiana Jones franchise.
20. The actor who played Charlie in Willy Wonka & the Chocolate Factory, Peter Ostrum, never acted again and is now a veterinarian.
21. Bill Murray could have been Batman. He was favourite to take the role until Tim Burton was put at the helm.
22. He was also originally considered for the role of Han Solo in Star Wars.
23. In Stephen King's novella for The Shawshank Redemption, Morgan Freeman's character Red is actually an Irishman. Hence Freeman's nod to it in the film with the quip, "Maybe it's cause I'm Irish".
24. The feces in the toilet that Ewan McGregor had to climb into in Trainspotting was made from chocolate.
25. The blood in the infamous Psycho shower scene? Chocolate syrup.
26. And while we're running with this theme: In Slumdog Millionaire the pile of excreta that the young Jamal jumps into was in fact made from a mixture of peanut butter and chocolate.
27. Franz Ferdinand were the original choice to play the band at the Hogwarts Yule Ball.
28. And Enya was James Cameron's first choice to compose the music for Titanic.
29. For his screen test for Star Trek Into Darkness, Benedict Cumberbatch recorded it in his best friend's kitchen using an iPhone.
30. Alfred Hitchcock's Psycho was the first American film to show a toilet flushing.
31. Whilst filming The Hunger Games, Jennifer Lawrence gave co-star Josh Hutcherson a concussion by accidentally kicking him in the head.
32. The real Frank Abagnale Jr. cameos in Catch Me if You Can as the French policeman who arrests Leo.
33. In Avatar the cigarette smoked by Sigourney Weaver is completely CGI, as she's a non smoker.
34. The slow-motion sound effect used in Dredd was inspired by a Justin Bieber song, slowed down by 800%.
35. In Saving Private Ryan, all the main actors were forced to endure a brutal weeklong soldier fitness boot camp — apart from Matt Damon, because directors intentionally wanted to generate resentment toward him and his character.
36. Bruce Willis is quite lucky he got to play John McClane in Die Hard at all. It was first written with Frank Sinatra in mind. Then Arnold Schwarzenegger, Sylvester Stallone, Burt Reynolds, Richard Gere, Harrison Ford, and Mel Gibson were all offered it first.
37. According to the Guinness Book of Records, The Lord of the Rings holds the record for the greatest number of false feet used in one movie: 60,000.
38. A year before filming started, 5,000 cubic metres of vegetables and flowers were grown to create the Hobbits' village.
39. Dougray Scott was the original Wolverine but was too busy filming Mission Impossible II, so he had to decline.
40. In Finding Nemo you can see a Buzz Lightyear action figure lying on the floor of the dentist's waiting room.
41. Also in Finding Nemo: If you wait long enough during the end credits, you'll see Mike from Monsters, Inc. swim across the screen with a scuba mask and fins.
42. Will Smith could have been Neo in The Matrix but he turned it down for a part in The Wild, Wild West. He has since admitted regretting the decision.
44. Toy Story is full of references to The Shining, including the same distinctive carpet in both Sid's house and the Overlook Hotel.
45. Michelle Pfeiffer turned down Silence of the Lambs, stating it was "too violent." It went to Jodie Foster.
46. Jodie Foster, meanwhile, landed the lead in Panic Room, but Nicole Kidman was being eyed up for the part until she injured her knee during Moulin Rouge.
47. David Bowie was offered the part of Captain Hook in 1991's Hook, but he rejected it.
48. Jennifer Lawrence may have never been Katniss Everdeen in The Hunger Games. Nine other actresses, including Emma Roberts, Hailee Steinfeld, Saoirse Ronan, and Chloë Moretz were also considered.
49. R2-D2 and C-3PO are hidden in the Hieroglyphs in Raiders of the Lost Ark.
50. Jim Carrey was supposed to play Buddy in Elf.
51. Before deciding on Brad Pitt, Fight Club producers initially wanted Russell Crowe to play Tyler Durden.
52. Initially, Lindsay Lohan was cast as Regina in Mean Girls, but she decided to play the "nice girl" so the public wouldn't base her real-life persona on Regina's.
53. Amanda Seyfried, meanwhile, was originally meant to play Lindsay's part, Cady.
54. Red's cell number (237) in Shawshank Redemption is the same number as the haunted room from The Shining.
55. Arnold Schwarzenegger's $15 million salary for Terminator 2 can be broken down to $21,429 per word.
56. The mask Michael Myers wears in Halloween is a Captain Kirk mask painted white.
57. The police officer in Hook is Phil Collins.
58. Sean Connery wore a toupee throughout all of his James Bond appearances.
59. Chewbacca's suits are made from a combination of yak hair and mohair.
60. Anthony Hopkins' total screen time in Silence of the Lambs was 16 minutes.
62. Carrie Fisher never wore a bra with this Princess Leia white costume.
63. In The Godfather, the baby used in Michael and Kay's baby christening scene is director Sofia Coppola, Francis Ford Coppola's daughter.
65. The blue lasers in Alien were borrowed from The Who, who were rehearsing on the soundstage next door.
66. In The Empire Strikes Back, the asteroid field included random objects — including a potato and a shoe.
67. Independence Day was shot in just 72 days.
68. In the first draft of the Anchorman script, the plot was to follow a planeload of news anchors who crash into another plane, which was carrying monkeys and martial arts equipment.
69. In Love Actually, Rowan Atkinson's character was originally meant to be an angel who would disappear as he walked away from Liam Neeson's character in the airport scene.
70. The original title of The Lion King was King of the Jungle — but it was later scrapped when the Disney production team remembered that lions don't live in the jungle.
71. In Ferris Bueller's Day Off, Charlie Sheen stayed awake for 48 hours straight so he could look wasted enough in the scene.
72. In Godzilla Matthew Broderick throws the driver's identification plate out of the window during the taxi chase scene. The name on the card is Armin Tamzarian — the real name of Principle Skinner in The Simpsons.
73. Back to Fight Club: There is a Starbucks cup visible in every scene of the film.
74. In Fast Five Han's full name is revealed as Han Seoul-Oh. Get it?
75. When Michael Caine sees The Joker for the first time in The Dark Knight, he was supposed to say some lines, but he was so taken aback by Heath Ledger's appearance (it was the first time he'd seen him) he "forgot every bloody line".
76. Ryan Gosling was cast as Noah in The Notebook because the director wanted someone "not handsome" or "cool."
77. To make Drew Barrymore's tears real in Scream, director Wes Craven repeatedly told her stories of animal cruelty.
78. Robert De Niro's most famous line in Taxi Driver, "You talkin' to me?" was unscripted. He improvised when he was told Travis had to speak to himself in the mirror.
79. Jack Nicholson also improvised infamous line "Heeeeere's Johnny" in The Shining.
80. There was real royalty in The Young Victoria in the form of Princess Beatrice — although blink and you'll miss her cameo.
81. In Pirates of the Caribbean, Geoffrey Rush asked to stand on the left of the shot whenever he was next to more attractive cast members such as Keira Knightley and Johnny Depp because he believes Western audiences tend to move their eyes from left to right.
82. Nicolas Cage was being lined up to play Superman in the 1990s, but it never materialised.
This post has been updated to meet BuzzFeed's sourcing and attribution standards. Four facts have been deleted because they were either incorrect or could not be sufficiently sourced.