What do you get when you mix one part action movie with one part holiday flick and add in a dash of sweaty tank top? Die Hard, John McTiernan’s genre-bending (Christmas?) action masterpiece for the ages, which sees a badass NYPD cop take on a skyscraper full of bad guys in the midst of an office holiday party. Here are 30 things you might not know about the movie, which was released on July 15, 1988.

1. Die Hard has a literary background.

Think some action-loving Hollywood scribe came up with the concept for Die Hard? Think again. The movie is based on Roderick Thorp’s 1979 crime novel Nothing Lasts Forever, which is a sequel to his 1966 novel, The Detective. In 2013, Thorp’s long out-of-print book was resurrected to coincide with the film’s 25th anniversary.

2. Die Hard was inspired by The Towering Inferno.

The idea for Nothing Lasts Forever was inspired John Guillermin’s 1974 disaster flick The Towering Inferno. After seeing the film, Thorp had a dream about a man being chased through a skyscraper by a group of men with guns. He eventually turned that snippet of an idea into a sequel to The Detective.

3. Frank Sinatra got first dibs on playing the role of John McClane in Die Hard.

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Because he had starred in the big-screen adaptation of The Detective, Frank Sinatra had to be offered the role in its sequel. At the age of 73, he smartly turned it down.

4. Bruce Willis's big-screen debut was with Frank Sinatra.

In 1980, Willis made his film debut (albeit uncredited) in the crime thriller The First Deadly Sin. He has no name and if you blink you’ll miss him, but the role simply required that Willis entered a diner as Sinatra’s character left it. Maybe it was kismet?

5. Clint Eastwood planned to take a stab at playing John McClane.

Originally, it was Clint Eastwood who owned the movie rights to Nothing Lasts Forever, which he had planned to star in in the early 1980s. That obviously never happened.

6. Die Hard was never supposed to be a sequel to Commando.

This is one of the most popular internet stories about Die Hard. But according to Stephen de Souza, the screenwriter of both Die Hard and Commando, while there was a sequel to Commando planned, the only similarity with Die Hard is that they both took place in buildings. According to de Souza, Escape Plan is the closest to his original Commando 2 idea and Die Hard was never supposed to be anything but Die Hard.

7. Bruce Willis was hardly the studio's first choice for the lead in Die Hard. He wasn't even their third choice.

If Die Hard was to be a success, the studio knew they needed a bona fide action star in the part, so they set about offering it to a seemingly never-ending list of A-listers of the time. Rumor has it that Sylvester Stallone, Harrison Ford, Robert De Niro, Charles Bronson, Nick Nolte, Mel Gibson, Richard Gere, Don Johnson, Burt Reynolds, and Richard Dean Anderson (yes, MacGyver!) were all considered for the role of John McClane. And all declined it.

8. Bruce Willis was considered a comedic actor when Die Hard came around.

Die Hard’s producers had nothing against Bruce Willis, of course. He just wasn’t an immediate choice for the role because, up until that point, he was known solely as a comedic actor, not an action star. Following the success of the film, the action genre really became Willis’s bread and butter, and although he has two Emmys for his comedy work, it has remained as such to this day.

9. Bruce Willis was barely even seen on the posters for Die Hard.

20th Century Fox Home Entertainment

Because the studio’s marketing gurus were unconvinced that audiences would pay to see an action movie starring the funny guy from Moonlighting, the original batch of posters for the film centered on Nakatomi Plaza instead of Willis’s mug. As the film gained steam, the marketing materials were altered, and Willis was more prominent in the promos.

10. Bruce Willis was paid $5 million for Die Hard, which was considered a pretty major payday at the time.

Even with all the uncertainly surrounding whether he could pull the film off, Willis was paid $5 million to make Die Hard, which was considered a rather hefty sum at the time—a figure reserved for only the top tier of Hollywood talents.

11. Bruce Willis suggested Bonnie Bedelia for the part of his wife in Die Hard.

Though we suspect that she wasn’t paid $5 million for the gig.

12. Bruce Willis was able to accept the role in Die Hard thanks to a well-timed pregnancy.

The first few times Bruce Willis was asked to star in the movie, he had to say no because of his commitments to Moonlighting. Then costar Cybill Shepard announced that she was pregnant. Because her pregnancy wouldn’t work within the show, producer Glenn Caron gave everyone 11 weeks off, allowing Willis to say yes.

13. Sam Neill was originally approached to play the role of Hans Gruber in Die Hard.

But Neill ended up turning the film down. Then, in the spring of 1987, the casting director saw Alan Rickman playing the dastardly Valmont in a stage production of Dangerous Liaisons and knew they had found their Hans.

14. Die Hard was Alan Rickman's feature film debut.

Though Rickman may have played the part of Hans as cool as the other side of the pillow, it was actually his first role in a feature film.

15. John McTiernan originally passed on directing Die Hard—more than once, too.

And not just once, but on a few different occasions. His reason was that the material just seemed too dark and cynical for him. “The original screenplay was a grim terrorist movie,” McTiernan told Empire magazine in 2014. “On my second week working on it, I said, 'Guys, there's no part of terrorism that's fun. Robbers are fun bad guys. Let's make this a date movie.’ And they had the courage to do it.”

16. John McTiernan sees Die Hard as a Shakespearean tale.

In the original script, the action in Die Hard takes place over a three-day span, but McTiernan—inspired by Shakespeare’s A Midsummer Night’s Dream—insisted that it be condensed into a single evening.

17. Die Hard's Nakatomi Plaza is actually Fox Plaza.

Fox Plaza played the part of Nakatomi Plaza. Tristan Reville , Flickr

Yes, the corporate headquarters of 20th Century Fox—the very studio making the movie—proved to be the perfect location for the movie’s much-needed Nakatomi Plaza. And as it was still under construction, there wasn’t a whole lot they needed to do to the space to make it movie-ready. The studio charged itself rent to use its own space.

18. The room where the hostages are held in Die Hard is supposed to be Frank Lloyd Wright's Fallingwater.

"In this period, Japanese corporations were buying America," production designer Jackson De Govia said in the Die Hard DVD audio commentary. "We posited that ... Nakatami Corporation bought Fallingwater, disassembled it, and reassembled it in the atrium, like a trophy."

19. The panoramic view of the city below in Die Hard? It's not real.

A 380-foot-long background painting provided the illusion of a breathtaking city view in the movie. And it was a state-of-the-art one, too, with animated lights, moving traffic, and the ability to change from night to day. The painting is still the property of the studio and has been used in other productions since.

20. Die Hard's success spawned a bona fide franchise.

In addition to its four sequels, Die Hard has spawned video games and comic books, too.

21. John McClane's tumble down a ventilation shaft in Die Hard was an accident.

Or maybe “error” would be a better word. But in the scene in which McClane jumps into an elevator shaft, his stunt man was supposed to grab onto the first vent. But he missed. By a lot. Which made the footage even more exciting to watch, so editor Frank J. Urioste kept it in the final cut.

22. Alan Rickman's death scene in Die Hard was also pretty scary.

At least it was for Rickman. In order to make it look as if he was falling off a building, Rickman was supposed to drop 20 feet onto an air bag while holding onto a stunt man. But in order to get a genuinely terrified reaction out of him, they dropped him on the count of two—not three, as was planned.

23. Bruce Willis suffered permanent hearing loss from shooting Die Hard.

Twentieth Century Fox

In order to get the hyper-realism that director John McTiernan was looking for, the blanks used in the guns in the movie were modified to be extra loud. In one scene, Willis shoots a terrorist through a table, which put the action star in extremely close proximity to the gun—and caused permanent hearing loss. He referenced the injury in a 2007 interview with The Guardian. When they asked Willis his most unappealing habit, he replied that, “Due to an accident on the first Die Hard, I suffer two-thirds partial hearing loss in my left ear and have a tendency to say, ‘Whaaa?’”

24. Alan Rickman wasn't thrilled with how noisy Die Hard was either.

Whenever he had to shoot a gun in the film, Rickman couldn’t help but flinch. Which forced McTiernan to have to cut away from him so that his reactions were not caught on film.

25. Hans Gruber's American accent in Die Hard caused a lot of problems.

The scene in which Rickman, as Gruber, slips into an American accent and pretends to be yet another hostage who got away was insisted on by screenwriter Steven de Souza, who wanted them in a room together to duke it out. But McTiernan was never happy with Rickman’s American accent, saying, “I still hear Alan Rickman’s English accent. I was never quite happy with the way he opened his mouth [in that scene] ... I shot it three times trying to get him to sound more stridently American ... it’s odd for someone who has such enormous verbal skills; he just had terrible trouble getting an American accent.”

26. The German Hans Gruber speaks in Die Hard is mostly gibberish.

And the bulk of his German cohorts were not German either. Bruce Willis, on the other hand, was actually born in West Germany to an American father and a German mother.

27. Bruce Willis has four feet in Die Hard.

As Willis spends much of the movie in his bare feet running through broken glass, he was given a pair of rubber feet to wear as a safety precaution. Which is great and all, but if you look closely in certain scenes, you can actually see the fake appendages.

28. You can see (but can't touch) John McClane's sweaty tank top.

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In 2007, Willis donated the blood-soaked tank top he wore in Die Hard to the National Museum of American History at the Smithsonian.

29. Die Hard's famous “Yippee-ki-yay" line stole the movie.

It was a simple line: “Yippee-ki-yay, motherf*cker!” But it became the film’s defining moment, and the unofficial catchphrase that has been used in all four Die Hard sequels as well.

30. The credit for Die Hard's famous “Yippee-ki-yay" line belongs to Bruce Willis.

In a 2013 interview with Ryan Seacrest, Bruce Willis admitted that “Yippee-ki-yay, motherf*cker!” was really just a joke. “It was a throwaway,” said Willis. “I was just trying to crack up the crew and I never thought it was going to be allowed to stay in the film."