One of the best Christmas films ever - yes that's right, it's a Christmas film - Die Hard is over 30 years old now and is still equally beloved for its quality and divisive for its festive movie status.
Nevertheless, from Bruce Willis' casting to Alan Rickman's American accent to that catchphrase, Die Hard could easily have been a very different film and may not have gone down in history as the best Christmas action film ever (niche as that category is).
With the film available to stream on NOW TV this holiday season, here are 30 facts about the Christmas classic.
1. It was Alan Rickman's first film
It's hard to imagine now, but prior to Die Hard Alan Rickman had never appeared in a feature film and was mostly known for his stage and TV work in the UK. In his debut the then 41-year-old then played one of the greatest screen villains of all time - a skill he would grow especially famous for.
2. Bruce Willis suffered hearing loss on set
Despite all the beatings John McClane took, including some nasty glass cuts on his feet, Willis' ears were the only body part to suffer real-life damage. Extra-loud blanks were used for realism during filming, and a scene where Willis shoots a terrorist through a table left Willis losing two-thirds of his hearing in his left ear.
3. It's based on a book
Along with Apocalypse Now and Rambo, Die Hard is one of those legendary films few realise was based on a book. The Bond-sounding Nothing Lasts Forever, written by Roderick Thorp in 1979, was a sequel to his 1966 book The Detective which was also turned into a movie starring Frank Sinatra.
4. The book was based on The Towering Inferno
Thorp first came up with the idea for Nothing Lasts Forever by falling asleep watching the Steve McQueen disaster film, and dreaming of a man being chased through a skyscraper by men with guns. That dream would then become the plot of his next book, and of course, Die Hard.
5. Nothing Lasts Forever went out of print
Despite inspiring one of the most influential action movies of all time, the book went out of print not long after the first film's release. Luckily the book was republished in 2013, just in time for Die Hard's 25th anniversary.
6. It's not a sequel to Commando
One of the most popular internet urban legends state that the film was originally meant to be a sequel to the 1985 Arnold Schwarzenegger action extravaganza and was later rewritten. Alas, this seems to be a case of fake news - while a sequel was in the work, screenwriter for both films Stephen De Souza has insisted that Die Hard was always meant to be standalone, and was never linked to Commando.
7. Frank Sinatra was nearly John McClane
Having played the lead character in The Detective film adaptation, producers were contractually obliged to first offer Sinatra the role despite him being aged 73 at the time. Sinatra turned it down, which is probably for the best - we can't imagine him running round in a vest shouting McClane's explicit catchphrase...
8. Clint Eastwood once held the rights
None other than Clint Eastwood held the movie rights to Nothing Lasts Forever in the early '80s and planned to star himself, but eventually passed on the project.
9. Bruce Willis wasn't even second choice for the role
After Sinatra and Eastwood turned the part down, Willis was far from a shoo-in for the role. Sylvester Stallone, Harrison Ford, Robert De Niro, Mel Gibson, Richard Gere and Burt Reynolds were all apparently considered or turned down the role before Willis was reluctantly cast.
10. Willis wasn't taken seriously as an action hero
Willis was known for his comedy work, particularly as David Addison in Moonlighting, and seemed far from the action legend we know today. Therefore the early marketing material barely featured him - the Nakatomi Plaza building got more coverage.
11. Bruce Willis was paid $5million to star
Now $5million is still plenty of dollar today, but was an unheard-of fee for a film role at the time and had to be personally approved by Fox President Rupert Murdoch. Not bad for someone who wasn't even third choice.
12. Fox charged itself to rent Nakatomi Plaza
The legendary Nakatomi Plaza was actually the 20th Century Fox Headquarters, and as a true stickler for the rules the company charged itself rent to use the unfinished building.
13. The bear Mcclane gives his kids was also in The Hunt for Red October
The Stan Lee of teddy bears, the exact plush bear John McClane gives his kids was also used by director John McTiernan as a gift for Jack Ryan's daughter at the end of The Hunt for Red October.
14. Sam Neil was offered the part of Hans Gruber
Yes, Jurassic Park's gentle Alan Grant nearly robbed Alan Rickman of his career-making role. Neil turned the part down, however, and Rickman was spotted by a casting director while playing the villain in stage play Dangerous Liaisons.
15. The film was influenced by Shakespeare
The book originally had events taking place over the course of three days, but director John McTiernan condensed this to a single evening after reading A Midsummer Night's Dream.
16. Alan Rickman kept flinching from the guns
Despite playing one of the greatest movie villains of all time, Rickman himself wasn't as keen on the gunfire. McTiernan had to cut away from his face every time his character fires a gun, and you can see him wincing if you look closely when Hans shoots Takagi.
17. The German terrorists don't speak German
Hired for their menacing looks rather than language skills, most of the German terrorists are speaking broken German gibberish. This was dubbed over in home video releases, but you can see their lips are out of sync. Ironically Bruce Willis, the all-American protagonist, was more German than most of the terrorists - he was born in West Germany to a German mother.
18. McClane's fall down a ventilation shaft was an accident
The stuntman was supposed to grab the first vent, but missed and continued to fall. The shot was used anyway, and edited with footage where McClane grabs the second vent (and the stuntman didn't slip).
19. Alan Rickman chose his costume
Originally Hans Gruber was to wear generic terrorist gear, but Rickman had the bright idea of dressing in a suit so he could later put on an American accent and pretend to be a hostage. He left a note for producer Joel Silver, and it was written into the script, which was constantly changed and tweaked during production.
20. Alan Rickman's surprise during the death scene was real
A well-known internet fact, although Rickman did not fall down the Nakatomi Plaza he did have to fall 20 feet onto an airbag. But the stunt man dropped him at the count of two, not three - leading to his genuinely terrified reaction.
21. Bruce Willis had fake feet
Die Hard is a movie with Tarantino levels of feet shots, but for the scene where McClane runs barefoot on glass in the computer room, Willis was given feet-like rubber shoes to wear. You can see the unnaturally large appendages if you look closely during the barefoot scenes.
22. John McClane's tank top can be seen in the Smithsonian
In 2007 Bruce Willis donate the sweaty, bloody tank top he wore in the first movie to National Museum of American History at the Smithsonian. Be warned - the top is far from its original white colour...
23. The panoramic view of the city below was fake
Long before the days of computer-generated backgrounds, Die Hard instead used a 380-foot long background painting, complete with lights, moving traffic and night and day modes.
24. Bruce Willis didn't cast Bonnie Bedelia
A popular internet asserts that Willis himself suggested Bedelia for the role of his estranged wife, but this was not the case. Willis told Entertainment Weekly, "No, Bonnie had already had some hits so I don't think I was responsible for that."
25. The villains were orignally terrorists
Who said they were terrorists? The original script!
It's hard to imagine Die Hard becoming the Christmas classic it is today had they stuck with the original plan of a gritty terrorist film. Luckily McTiernan changed the terrorists to robbers to avoid a political angle, and added a focus on McClane's relationship with his wife to make it more of a date movie.
26. The title doesn't translate well
English idiom Die Hard would translate literally as "It is hard to kill" or "He dies slowly", meaning marketers had to get creative. Therefore the film is "Lethal Trap" in the Czech Republic, "Action Skyscraper" in Norway, "The Glass Trap" in Poland and "Hard Nut" in Russia. And then there's Hungary, which christened the film "Give your life expensive"...
27. Bruce Willis came up with the Yippee Ki-yay catchphrase
Willis amended the original line to make the crew laugh while messing about on set, never thinking it would be kept in the film. It became so iconic that it has appeared in every sequel since.
28. People were working in the building during filming
The building was still partially used during filming, and funnily enough the workers didn't appreciate the constant gunfire. McTiernan often had to send someone to apologise for the noise.
29. The scene where McClane and Gruber first meet was unrehearsed
The brainchild of Alan Rickman, the meeting between John McClane and "hostage" Hans Gruber was unrehearsed to create more spontaneity between the two.
30. It IS a Christmas film
Bruce Willis may think otherwise, but 20th Century Fox pretty much confirmed it with the release of this trailer for "The Greatest Christmas Movie"...