When it comes to Marvel movies, it's a damn good time to be a comic book fan. Whether you prefer the ever-expanding saga of the Avengers in the Marvel Cinematic Universe from Marvel Studios or the trials of the X-Men, Wolverine and Deadpool from Fox, theaters aren't short on films that feature our favorite characters on the screen. But these characters aren't the only things that transitioned from the comics to the screen. So too did some of their most famous events.

RELATED: The 15 Most Mind-Blowing Moments In Marvel Events

Popular events like "Civil War" and "Age of Apocalypse" were loosely adapted to the screen, and now both "The Infinity Gauntlet" and "The Dark Phoenix Saga" are set to arrive on our screens as soon as next year. But not all Marvel Comics events can be adapted to the screen. In fact, some of them are so intricate and far-reaching, their casts so big and varied, that their fans will never see them in the theater. Join us today as we take a look at 15 Marvel Comics events, be they famous or infamous, that will never be adapted on film.

15 SECRET WARS

secret-wars

In 1984, Marvel Comics published a series written by Jim Shooter and illustrated by Mike Zeck and Bob Layton. It was called "Secret Wars" and it told the story of a cosmic being named the Beyonder who brought Earth's mightiest heroes and villains to a planet called Battleworld. It was a big event for Marvel, one that spawned a sequel the following year, and a very different spiritual sequel of the same name in 2015. The series was notable, among many things, for introducing the alien symbiote that turned Spider-Man's costume black, leading to the creation of Venom.

The series was big and exciting and everything comic books should be... and yet, there is no way it could ever appropriately be adapted to the screen. For one thing, fan-favorite characters like the X-Men, the Fantastic Four and Doctor Doom -- all notable and important characters in the series -- would never be allowed to appear in a movie adaptation thanks to Fox owning their movie rights. But it's not even just about the characters. It's also the fact that "Thor: Ragnarok" will explore a story about a cosmic character bringing heroes to a planet to battle each other. Marvel Studios isn't one to repeat itself... well, so blatantly, anyway.

14 ORIGINAL SIN

Marvel-event-Original-Sin

At its core, "Original Sin" -- by writer Jason Aaron and artist Mike Deodato -- was a murder mystery, a whodunit story that started with the puzzling murder of Uatu The Watcher, an ancient and powerful being as old as the Universe itself, pledged to observe life on Earth but never interfere with it (a rule that he had broken on many occasions to help Earth's heroes.) With the Watcher gone, all of the secrets he had come to know over his years watching over mankind, everything he knew about the world's heroes and more, had been laid bare.

RELATED: Who Watches The Watcher: 15 Times He Broke His Vow

These secrets reached far and wide into the heroes' past to reveal something they hadn't known before, some going all the way back to their origins, like the revelation that the spider who had bitten Peter Parker had also bitten someone else. "Original Sin" saw a twist in the revelation of Uatu's murderer -- Nick Fury -- a revelation that revisited the character's history and that turned him into a quasi-villain. This may have worked in the comic book world, but this wouldn't be in keeping with the Fury character we have come to know in the movies. And that's not even mentioning that we don't even know if Uatu exists in the MCU.

13 CIVIL WAR II

Even while considering that we have seen an adaptation of the first line-wide event in "Civil War," on-screen in "Captain America: Civil War" -- the final movie in Steve Rogers' own trilogy -- there is little chance that we would ever get to see the sequel event "Civil War II" actually make it on the screen. "Civil War II," by Michael Brian Bendis and David Marquez, was a confrontation between Iron Man and Captain Marvel, whose differing opinions on how best to use a young new Inhuman's precognitive powers put them, and the rest of the Marvel heroes, at odds.

While the subject matter is just as simple in its basic idea as the one behind the first event, there is little chance that Marvel Studios would ever revisit that well. The last "Captain America" film was a triumph that pleased both fans and critics and we doubt that Marvel Studios would ever choose to construct a film once again on the idea of heroes fighting heroes. It's a sort of marketing campaign that can only work once for a movie-going audience. A second go around wouldn't nearly be as shocking, surprising or engaging.

12 AXIS

Marvel Axis event with villains like Loki and Doctor Doom

The basic premise behind the Marvel event "Axis" by writer Rick Remender was that the main villain of the story, the Red Skull, had now gained control of Charles Xavier's telepathic brain and he used it to spread hate across the world. In a great turn of events, the Marvel Universe saw some of its most famous characters inverted: the heroes turned bad and the villains turned good (or rather better), the crazies into the zen and the hopeful into the frightful. But while this sounds like an interesting read, it's one that couldn't really work on film.

With the event revolving so much around both "Avengers" and "X-Men" characters, the simple fact that both teams cannot share the same screen thanks to their rights belonging to different studios -- Marvel and Fox, respectively -- makes this adaptation very unlikely. On top of that, there is the Red Skull as the main threat of this event, a villain we haven't seen since "Captain America: The First Avenger." Considering all of that, we doubt we will ever see the good guys turn bad and the bad guys turn good in an "Axis" movie.

11 SPIDER-VERSE

Every Spider-Man ever in Spider-Verse

"Spider-Verse" by writer Dan Slott was an event that involved any and all versions of Spider-Man that fans had come to know over the years. Spider-Men and Women from every alternate reality imaginable were all under attack from a villain named Morlun and his Inheritors. It was a wide and sprawling event that took readers to many alternate versions of Earth, a story that saw these Spider-Men and Women unite to form a Spider-Army so that they might survive.

Simply put, this event is so big that it could sadly never happen. With Tom Holland only starting his career as Spider-Man, little is known about what will happen to the character after his involvement in the "Avengers" movies and his two solo films under Marvel Studios' care. While the idea of having Peter travel to other versions of Earth and uniting previous Spider-Man versions like those played by Tobey Maguire and Andrew Garfield (and maybe even Emma Stone as Spider-Gwen!) sounds amazing, we doubt the movie studios would ever allow that to happen.

10 SECRET INVASION

What made "Secret Invasion" work as an event with deep consequences was that its seeds were planted early on. Years early, in fact. The event wasn't even planned when writer Brian Michael Bendis started preparing for it in his "New Avengers" run. There were just hints and quick glimpses of shadowy figures working in the dark, until came the revelation that the person everyone thought was Elektra had been a shape-shifting Skrull. For how long? And why?

These questions led the Avengers to distrust, each unsure of who else could secretly be a Skrull, from the dearly departed and returned to life to the ones who had seen an evolution in personality. It was a distrust that allowed the Skrulls to attempt a full-blown invasion of Earth, one that almost proved successful. Considering that there is no way the movies can go back and plant the seeds for an invasion by the Skrulls -- characters they don't even have the right to use thanks to a deal with Fox -- we don't think we will ever see this great story come to life on screen.

9 WAR OF KINGS

black bolt war of kings

Written by fathers of the modern Marvel cosmic universe Dan Abnett and Andy Lanning, "War of Kings" saw every major character from that corner of the universe involved in some way. The Guardians of the Galaxy, the Starjammers, the Shi'ar, the Nova Corps and the Kree all featured in the pages of the event as the evil mutant Vulcan, finding himself Emperor of the Shi'ar, brought war to the Kree, who were led by Black Bolt, king of the Inhumans.

The sheer number of characters involved, not to mention all of the differing rights issues, will always prevent this event from coming to the screen. With Vulcan being the brother of the X-Man Cyclops, with the Shi'ar similarly tied to the X-Men universe, and with Black Bolt, the Inhumans, the Kree and the Guardians belonging to Marvel Studios, this exciting space-spanning event will sadly have to be bastardized beyond recognition if there is ever any hope of seeing it adapted to film.

8 WORLD WAR HULK

world-war-hulk

The Marvel Comics event "Planet Hulk" saw the green giant exiled by those he once called friends to a far away planet where he was forced to fight for survival in a battle arena. With "Thor: Ragnarok" looking to partially adapt this story to the big screen, we just can't see its follow-up, "World War Hulk," getting the same treatment. Little is known of how the Hulk came to find himself on a different planet in the movie, but it seems very unlikely that he was sent there by his friends.

In what looks to be more like a self-imposed exile following the events of "Avengers: Age of Ultron," it's unlikely that the Hulk would return to Earth to exact revenge on those who had sent him away. Written by Greg Pak and illustrated by John Romita, Jr., "World War Hulk" saw Tony Stark and his fellow members of the Illuminati face the consequences of their actions against the Hulk. With the relationship between Stark and Banner being such an amicable one in the movies, we can't, for one second, imagine Stark sending his friend away to worlds unknown.

7 SPIDER-ISLAND

spider-island-header

The "Spider-Island" event by Dan Slott and Humberto Ramos was featured in the "Amazing Spider-Man" series, as well as many separate one-shots, and had a story that saw the Avengers quarantine the island of Manhattan after its citizens started developing spider-powers not unlike those of Peter Parker. It was an event focused on a more mature, more experienced Peter Parker that involved all of the important Spider-Man characters, as well as the Avengers, the Fantastic Four and others like Squirrel Girl and Cloak and Dagger.

Sure, the story could be changed to remove the involvement of characters Marvel doesn't have the rights to, but this is still a story that involves many characters. With the new "Spider-Man: Homecoming" film bringing the Vulture to the screen, its sequel will no doubt focus on another classic Spider-Man character -- not an island of New York infested with spider-powered people, something so big that it would require the involvement of characters played by actors whose contracts will all mostly be up by the time cameras roll.

6 ANNIHILATION

Marvel annihilation

While the Earth's heroes were fighting each other over the Super-Human Registration Act in "Civil War," Richard Rider, aka Nova, teamed-up with Drax The Destroyer and the greatest heroes in the galaxy to save the Universe itself from the threat of the Annihilation Wave in the astonishing space event "Annihilation." It was an event that involved every main character in Marvel's cosmic arsenal and turned this corner of the universe into what readers know it to be today.

In the MCU, the cosmic side of the Marvel Universe is mainly being explored by the "Guardians of the Galaxy" movies. While great, neither of those movies were direct adaptations of any comic book storyline and we doubt that will change for the future third instalment in the series. Besides, we may not know what the plans for phase 4 of the MCU will be, but we doubt it will once again have an overarching story about an army of aliens attacking the universe.

5 THE KREE/SKRULL WAR

Kree Skrull War

"The Kree/Skrull War" was an event that unfolded in the pages of "The Avengers" comic book. Written by Roy Thomas, it saw the Avengers, Rick Jones and the male version of Captain Marvel, Mar-Vell, finding themselves protecting the Earth from being annihilated by the Kree and Skrull Empires who were locked in an intergalactic war. As it stands, it's difficult to imagine this story being adapted to the screen, especially with Captain Mar-Vell playing such a large role in the event.

Brie Larson may have been cast as the female version of the character, but we do not yet know if her powers are tied in any way to the Kree, or if she will be around long enough to see one of her movies see her involved in a war between two alien races. And even if she could occupy Mar-Vell's role, there is also the fact that Marvel Studios are not allowed to use the Skrulls in their movies. While they could replace them with another alien race, the spirit of the event would then be lost in the process.

4 HOUSE OF M

X-Men House of M

After tragically losing her children, Wanda Maximoff -- aka The Scarlet Witch -- used her powers to her fullest and most awesome capabilities and created a new version of reality, a world where her father Magneto reigned supreme and where the mutants ruled over the humans in an event called "House of M," by creators Brian Michael Bendis and Olivier Coipel. Wolverine was the only one who remembered the world before, and he joined the human resistance led by Luke Cage in the hopes of returning things to normal.

An X-Men-heavy event, "House of M" also featured several other important characters like Spider-Man, the then-Ms. Marvel and Doctor Strange. It would be possible for the "X-Men" movies to adapt this story into a movie that only features mutants, but without the involvement of some of the MCU characters, not to mention the absence of Hugh Jackman -- who has now famously retired from the Wolverine role -- there is little chance we will ever see a real version of "House of M" reach the big screen.

3 THE CLONE SAGA

Spider-Man Clone Saga

The infamous '90s Spider-Man event "The Clone Saga" took over all of the "Spider-Man" titles at the time for a story that spanned almost three years and dozens upon dozens of issues. A story that focused on the revelation that the Peter Parker we thought we knew was a clone, it was a very popular yet controversial event, even to this day. While it was later disclosed that this clone revelation had been a lie, the story itself had become one that every Spider-Man fan knows of.

While easily one of the more popular and recognizable events of the '90s, there is little chance that we will ever see "The Clone Saga" adapted into film. First of all, the story was largely convoluted and didn't lead to many lasting effects, if not for the introduction of Kaine and some emotional change in Peter Parker. And besides, we have a hard time imagining clones of Tom Holland running around in a more grounded Marvel Cinematic Universe, no matter how crazy the science can sometimes get over there.

2 AVENGERS VS. X-MEN

Cyclops shoots optic beams at Captain America's shield in Avengers vs X-Men

The "Avengers vs. X-Men" event came at a time when the mutant population of Earth was near extinction levels. The Phoenix Force came to Earth looking for a new host, and the X-Men believed that its arrival would bring with it a rebirth of mutantkind. But the Avengers saw the Phoenix as a threat, a powerful entity capable of ending all life on the planet, mutant and human alike. This difference in opinions led to an all out war between the two super-teams that used to be friends and allies.

Simply put, the reason we will never see this event adapted on film is because there is no way we will ever see the Avengers and the X-Men share the screen. As stated multiple times in this list, the fact that Fox owns the X-Men film rights prevents the two teams from ever meeting. We hope with all our hearts that an agreement between the two studios could be made to see our two favorite superhero teams crossover, but we don't see that eventuality coming to pass any time soon, let alone in a conflict like this one.

1 DC VS. MARVEL

Even more of a logistical and legal nightmare of improbabilities than the Avengers meeting and fighting the X-Men would be a crossover between two very different universes and studios. While the X-Men are technically under the same cinematically loose Marvel banner as the Avengers, the Justice League and other DC Comics characters belong to another competing company, a different reality altogether. "DC vs Marvel" was a mid-90s event written by Ron Marz and Peter David that saw the two universes cross over. But a meeting on the page is much easier than on the screen.

With the DCEU movies still finding their footing and only nearly reaching the formation of the Justice League, some will say that there is a rivalry between the two companies, a rivalry that will forever prevent such a cinematic event from taking place. While the comic book event may have given fans of both companies, or either one, the chance to see their favorite characters fighting each other, moviegoers will have to read the pages of the comics if they have any hopes of seeing Batman and Captain America interact. But sometimes, things are just better left exactly there: on the page.

Which Marvel event would you like to see on-screen? Be sure to let us know in the comments!