Music is just one of the tools in the filmmaker's toolbox that helps to heighten emotion and triggers a sense memory, transporting us back to a film's character, scene, or world. There are other such tools, like cinematography, lighting, editing/pacing, and so on. Music is one of the most powerful of these, because it can be enjoyed with the movie or outside of it.

But sometimes a movie comes along that just can't live without its score.

It's that rare musical composition that so perfectly captures the essence of the movie it's set to, that it's ingrained into our hearts and minds as part of the movie's DNA. It's not just "good" music or "popular" music. We're talking about music that defines a film, music that's part of a movie's very identity, music that the film simply can't be the same without.

Take this music away, and you have a fundamentally different movie. You'll see what we mean. Here are 15 Movies That Can't Exist Without Their Musical Scores.

15. Inception - by Hans Zimmer

Inception Poster

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Fresh off his mega-successful The Dark Knight, Christopher Nolan set out to craft a mind-bending thriller set in the subconscious mind where dreams happen. For the ultra-secretive project, Nolan once again turned to his longtime musical collaborator, Hans Zimmer, who created a musical score as lush and diverse as the imaginative world-building Nolan did in the movie.

Zimmer's work has always been influenced by classical music, and that's ever-present in his Inception score. But the Inception soundtrack is so much more, like a cross-section of every kind of music Zimmer is capable of. In addition to the usual dramatic and exciting stuff, he dabbles in meditative, electronica, and ambient sounds. It feels like a "best of" collection of tracks from multiple kinds of movies, before Zimmer pulls it all together for the movie's climax.

It's within this unforgettably huge, Russian doll-like contraption of dreams within dreams within dreams, where time works differently within each layer, that Hans Zimmer's score becomes indispensable. It's a multilayered, sonic equivalent of an hourglass inside a grandfather clock inside Big Ben; it keeps your heart pumping like mad even when the action slows to a crawl on the screen. In the hands of a lesser composer, Inception could have been a self-important, overwrought mess. Zimmer uses music not only to underscore the film's emotions but its very complex construction as well. It's the glue that unites Inception's pieces and holds it all together.

14. Halloween - by John Carpenter

The opening titles to Halloween (1978).

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Halloween's simple piano line has the cadence of a "breaking news" intro, until it quickly turns sinister and worms its way into your brain. Such was the genius of every aspect of John Carpenter's classic horror film about the disturbed, white mask-wearing serial killer named Michael Myers.

For today's audiences, horror means a big, outlandish, gross-out, jump-scare-athon. But once upon a time, when horror was in its infancy, it was arguably a purer, more subtle affair. Maybe we were living in simpler times, so the psychological aspects of horror were more potent than they are in today's cynical world. Whatever the reason, Carpenter tapped into that sensibility to craft his minimalist horror masterpiece, Halloween.

Carpenter himself composed the score, and you have to wonder if it came to him at the same time he first dreamed up the story, because they're so thoroughly part and parcel of the same enterprise that it's impossible to imagine one without the other.

13. Jurassic Park - by John Williams

Jurassic Park logo and animated series artwork

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Without John Williams' music, Jurassic Park would be a very different movie.

It goes without saying that Williams is a legend, one of the all-time greats. He's given us so many magnificent film scores — and every single one of them so remarkably memorable, we start humming them to ourselves as soon as they're mentioned. (You'll find several of them in this very article.) There's simply no one else like him, and it would have been very easy to fill this entire list with Williams' work.

In narrowing down his most essential work, it's impossible to ignore his themes for Jurassic Park. Williams' greatest strength is his ability to conjure a melody that fits perfectly fits a film's subject matter, and Jurassic Park is a quintessential example. It's patently impossible to think of Steven Spielberg's dinosaur classic without hearing Williams' majestic tune in your head. It beautifully conveys the awe audiences feel while watching realistic depictions of dinosaurs on screen for the first time ever. Not only that, it's music that would work in-universe too, as if played at the titular theme park at the moment that visitors arrive. It's alo completely sincere; there's not a trace of self-awareness or irony to be found.

Its start as a gentle lullaby speaks to the notion of creatures only ever seen in the imagination that have finally come to life. From there it slowly builds into a bombastic anthem that's embedded itself into our culture so deeply that... Forget the movie, it's hard to think of dinosaurs without hearing Williams' music in your head.

12. Batman - by Danny Elfman

Batman 1989 Movie Tim Burton

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Although it's aged by today's standards, back in 1989, no one had ever seen anything like Tim Burton's Batman. In fact, the sentiment expressed by the public at large when the movie was first announced was, "Why?" Why do a serious, big-budget take on a campy TV show from the 60s? Why make a movie about a comic book superhero who has no superpowers?

Burton answered every critic with a staggering achievement: a industrial, gothic take on the Batman myth which formed a whole new template for Hollywood to work with. And that template is still being riffed on by filmmakers today. Danny Elfman elevated Burton's work with a dark-and-brooding score that stated very clearly that this Batman may not exist in the real world, but he was a character to be taken one hundred percent seriously nonetheless.

Another composer could have written a serviceable score for this movie. But Elfman's understanding of Burton's sensibilities allowed him to craft an inventive opus that combines two styles that have nothing to do with superheroes -- "gothic romance" and "dark fairy tale" -- in a way that works beautifully. Employing a huge, lush orchestra to bring his ideas to life — not to mention clever use of a pipe organ to evoke an enchanting, baroque feel — Elfman still managed to insert a hint of the whimsy he's known for.

11. Gone With the Wind - by Max Steiner

Poster for Gone with the Wind showing Clark Gable and Vivien Leigh.

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A sweeping love story for all time. An epic recreation of the Civil War and the Burning of Atlanta. A soapy drama about the intimate politics of a Southern plantation. Whatever you want to call it, if you adjust historic ticket prices for inflation, Gone With the Wind is still the number one box office money maker of all time. What that means is that more people went to the cinema to see this movie than anything else, ever.

So Gone With the Wind's music better be pretty darn memorable. And it is; most people, even today, could hum its main theme. That's remarkable, given that we're talking about an almost 80-year-old film. In the history of movies, there may be no more romantic melody than "Tara's Theme" from Gone With the Wind. It may have been named after the movie's physical setting, but history has eternally recorded it as the sound of the passionate, torrid love between Scarlett O'Hara and Rhett Butler.

It shouldn't be terribly surprising that the score still works to this day. Composer Max Steiner knew a thing or two about writing romantic music; his credits are filled with classics like Little Women and Casablanca.

10. E.T. - by John Williams

The bike scene in E.T. the Extra Terrestrial

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You could call E.T. an adventure, but what it really is, when you boil it down to its most basic moving parts, is a tearjerker. The little alien who got left behind by his people befriends a pair of doe-eyed kids, wants desperately to "phone home," is killed by fear-mongering adults but comes back to life, must leave behind the little boy who loves him when he finally returns home... Every twist in the script was intentionally designed to tug at your heartstrings.

So only an equally emotional score would do, and once again the Steven Spielberg/John Williams collaboration paid off. The average person can probably remember only a handful of movie scores (many of them being on this list) off the top of their head, but children of the '80s will always mark this among them.

Williams' work was a lofty ode to hope and wonder, a glimpse into the dreams of a child, and it's forever intertwined with the story, the characters, and E.T. himself.

9. Titanic - James Horner

Titanic VHS DVD cover

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Celine Dion notwithstanding, Titanic will always be the best known and most celebrated work of James Horner's prolific career. James Cameron reportedly hired the composer after hearing his work on Braveheart, because he was looking for a rich, emotive score with similarly Irish influences. Horner delivered a collection of stunningly emotional compositions that ran the gamut of joy and heartbreak, drama and action, passion and destiny.

Love it or hate it, there's no denying that Titanic is a spectacle, a feast for the eyes that transports viewers back to a more innocent age. It was a love story, a historical epic, and a tragedy all wrapped up together. Cameron took a huge risk in making it, and it famously went way over budget and blew past its production schedule. Pundits were expecting it to be the biggest flop of all time, but it instead withstood all the naysayers to become the highest grossing movie of all time (it's since been surpassed by Cameron's Avatar and domestically by J.J. Abrams' Star Wars: The Force Awakens). How much of that can be chalked up to Cameron's visual extravaganza, and how much to Horner's score?

It's impossible to quantify, but there can be no doubt that the one would not have embedded itself into history without the other. (And yes, that blasted Celine song helped, too.)

8. Close Encounters of the Third Kind - John Williams

A giant ship hovers above a group of scientists

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When we say "movies that can't live without their music," we're largely speaking metaphorically. But not in the case of Steven Spielberg's alien visitation classic, Close Encounters of the Third Kind.

Music is the major plot device that holds this film together. The story centers on a group of random individuals whose lives are changed forever after encountering UFOs that send them a subliminal message. The main characters eventually converge at a mountain in Colorado, where a five-note melody becomes the key to communicating with the alien visitors. Without that melody, the humans would never be able to communicate with the aliens. Composer John Williams came up with the melody that became synonymous with the film; in solfège terms (the technique used in The Sound of Music), the notes are "Re-Mi-Do-Do-So," with the second "Do" being an octave lower than the first.

Close Encounters also eschewed the traditional way of scoring a film. Typically, a film is shot and edited, and then the composer writes the score to follow the cues on-screen. For Close Encounters, Steven Spielberg asked John Williams to write the score first, before a single frame of film had been captured. Spielberg then shot and edited the film to the music. Putting the music first gave the movie an unusually lyrical framework.

7. Rocky - by Bill Conti

Rocky Ending

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Quick, think of the theme music to a sports movie — any sports movie. If you're like most people, you can probably only think of one or two. Jerry Goldsmith's Rudy has become popular over the years thanks to repeated use in movie trailers and whatnot. But there is no more famous sports movie music than Bill Conti's theme from Rocky. Admit it: you're hearing those trumpets in your head right now.

Rocky Balboa's personal struggle — a story injected with autobiographical material from star and screenwriter Sylvester Stallone's own life — is perfectly encapsulated and symbolized by Conti's inspirational melody. It comes close to sounding like the chorus to a pop song, making it the perfect anthem for the essential sports flick of all time.

Rocky is remembered for its main character's personal victory, but it was ultimately about perseverance. Conti's music transmits that determination so strongly that audiences were ready to lace up some shoes and follow Rocky Balboa on his run up those famous Philadelphia steps.

6. 2001: A Space Odyssey - by Strauss, Strauss, Khachaturian, & Ligeti

HAL5000 in 2001: A Space Odyssey

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Probably the most innovative score on this list, Stanley Kubrick's intentionally slow, cerebral, and sometimes confusing 2001: A Space Odyssey is remembered for its creative use of existing classical music. Rather than utilize an original score, the entire movie is set to the classical works of Johann Strauss, Richard Strauss (no relation), Aram Khachaturian, and György Ligeti.

The one piece of music that's synonymous with the film is Richard Strauss' "Also Sprach Zarathustra." Someone says "2001," and your brain goes, "Duh... Duh... Duh... Duh-duh!" It's the theme that plays when the monolith is first revealed, when the ape learns to use a tool, and when Dave Bowman transforms into the "Star-Child" at the movie's end. Can you even imagine 2001 without those notes and chords?

Johann Strauss' famous "Blue Danube" waltz is memorably employed when the PanAm craft docks at the space station, but that waltz has seen so many uses that it's not inseparable from 2001 the way "Zarathustra" is. And we can't leave out HAL-9000's chilling rendition of "Daisy Bell", which the A.I. sings itself, eerily symbolizing his calm insanity. "Daisy Bell" has left its own mark on the art form, still being used today to indicate a person or thing that's slowly gone mad.

5. Raiders of the Lost Ark - by John Williams

Indiana Jones Raiders Lost Ark Poster

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John Williams' score from Raiders of the Lost Ark includes the iconic Indiana Jones theme, the "Raiders March." When Indiana Jones became a franchise, "Raiders March" became Indy's personal theme music. Today, the iconic character and the iconic music are conjoined as one.

Director Steven Spielberg reportedly gave Williams a helpful nudge as the composer was putting together the music for Raiders. After Williams had narrowed down his ideas for the movie's main theme to two, he played both of them on the piano for Spielberg. The director loved them both so much that he encouraged Williams to combine them, and thus the Indiana Jones theme we know and love today was born.

Rousing, thrilling, dangerous, heroic... All words that can be used to describe "Raiders March" — and the movie it was written for. Would we even remember Indiana Jones as well as we do without John Williams' music?

4. The Godfather - by Nino Rota

Al Pacino as Michael Corleone The Godfather

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It's fitting that the world's most famous Mafia film saga was scored by an Italian composer. Nino Rota's main theme has an almost oppressive feel of familial loyalty, married to violins that radiate sorrow. It's the perfect sound to underscore the tone of Francis Ford Coppola's The Godfather, the classic tale of the ultimate fictional crime family.

The movie's every emotional moment masks its feeling of inevitability, a foreknowledge that Mafia families, with their combination of tradition and violence, are certain to meet a dark end. As much as it's compelling in its powerful drama, The Godfather is also kind of... well... depressing. And the same can be said of Rota's music — in the best way. The fascinating score invites viewers into the most intimate moments of the Corleone family, be it ugly or elegant.

The Godfather is known for its famous lines of dialogue, but can you hear Marlon Brando or Al Pacino uttering words like "I'm gonna make him an offer he can't refuse" or "Don't ask me about my business" without Rota's music behind them? We'd argue it's impossible.

3. Jaws - John Williams

Jaws poster art close-up

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DUH-nuh... DUH-nuh... DUH-nuh... The music from Jaws is unquestionably among the most iconic movie music of all time. That's fitting since Jaws was the world's very first blockbuster — the word comes from fans lining entire blocks around movie theaters, waiting to get in — and John Williams' score is the thing that people remember about the movie above all else. That unforgettable theme is utterly sinister, but has a hint of self-aware playfulness to it as well. Maybe that's why it clicked so well with audiences.

Yeah, the mechanical shark effects were cool, and sure the scenes of it hunting people underwater were terrifying. It's probably impossible to quantify how much of the movie's success is owed to Williams' music, but if ever a movie owed a portion of its place in history to its music, that movie is Jaws. Steven Spielberg himself is on record as believing that the movie "would only have been half as successful" without Williams' music, and Williams, despite having scored dozens of films and TV shows prior to Jaws, claims that it "jumpstarted" his career.

Perhaps most remarkable of all is the massive impact it made on music though much of it comprised of just two notes: E and F.

2. Star Wars - John Williams

Luke Skywalker New Hope

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"A long time ago in a galaxy far, far away..."

You know what happens next. The big yellow logo suddenly fills the screen while there's a loud blast of horns. With this, we know that Star Wars has arrived. It was hard not placing this at the top of our list, as the Star Wars score is probably the best-known movie music of all time. But this isn't about the most popular movie music; this is about movies that can't be separated from their music.

On that front, Star Wars still ranks very high. And not just for those famous opening horns, but for the entire incredible body of work that John Williams has written for all seven (and counting) Star Wars films. The stark, intense "Imperial March" told us just how evil Darth Vader and the Empire was. Luke Skywalker's wistful theme beautifully communicated the longing in his heart for adventure but the apprehension of his destiny. The sense of desperate longing underpinning the Han/Leia love theme, the commanding choir in the prequels' "Duel of the Fates." The list goes on and on.

The music is as inseparable a part of the saga as the Skywalkers.

1. Back to the Future - by Alan Silvestri

Michael J. Fox as Marty McFly in Back to the Future

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Never has a horn section sounded more triumphant, exciting, or epic. So many words could be used to describe Alan Silvestri's dynamic score for Back to the Future; as perfect a full body of work as any composer has ever created. It's our top pick for music that can't be excised from its movie without altering the movie's entire DNA, because it's so intrinsically entwined with the film.

Silvestri has given the world a number of beloved musical themes, such as those belonging to Romancing the Stone, Flight of the Navigator, Predator, Who Framed Roger Rabbit, Forrest Gump, Contact, and dozens of others. But when he crafted the music for Back to the Future — one of his earliest works as a composer — he tapped into something very special.

Think about the climactic scene where the DeLorean has to hit 88 miles an hour at the exact moment that a fateful bolt of lightning strikes the clock tower, enabling Marty McFly (Michael J. Fox) to return to his own time. This is a film that relentlessly tightens the screws, and every time you think the tension can't get any higher, it does. The music is an inextricable piece of that carefully-constructed house of cards, a glorious auditory manifestation of everything Back to the Future is, in musical form.

Take away Alan Silvestri's score, and what do you have left? Something that's not Back to the Future. And in no other film is that feeling more palpable.