The Marvel Cinematic Universe was born in 2008 with Iron Man. That landmark movie not only introduced the concept of S.H.I.E.L.D., it also offered a clever Easter egg about Captain America's shield, as well as featuring the debut of Samuel L. Jackson's Nick Fury. But the full idea of an interconnected universe actually came a few months later with The Incredible Hulk, a movie that ended with a surprise appearance by Robert Downey, Jr.'s Tony Stark. After that, the tapestry of the MCU only grew bigger, with the introduction of Black Widow, Thor, Hawkeye and Captain America -- and that was just for starters. Little did we know that this would lead to Doctor Strange, Spider-Man, the Guardians of the Galaxy, Black Panther and, of course, the ultimate ensemble movie, Avengers: Infinity War.

Twenty movies, 10 years, and one overarching storyline. Each film built from elements of the previous, to lead to something that was wholly unprecedented. But what about all of the scenes that were considered, but who were ultimately left out of the MCU? Each film, from Captain America: The Winter Soldier to Doctor Strange, features deleted scenes that could have changed the movies they were supposed to be in, and that maybe could have even altered the general course of the MCU. Some of these scenes were filmed, while others were only established in concept before being cut. Nevertheless, it's safe to say that had certain movie moments not been cut out, Infinity War might have been very different. Here is a rundown of 20 scenes that could have changed everything.

20 HULK SMASHES CAP OUT OF THE ICE

Before the plan to bring the Avengers together on the big screen was set in stone, there were only two movies to establish the idea of a shared cinematic universe: Iron Man and The Incredible Hulk. In the Jade Giant's solo film, there was a deleted scene that saw Bruce Banner transform into the Hulk in the North Pole.

In the scene, there is a very subtle Easter egg that shows the Hulk smashing a frozen Captain America out of the ice, as a nod to the comics. If that scene would have been kept, then Steve Rogers' entire presence in the Marvel Cinematic Universe's modern times would have been altered, as would his first solo movie.

19 HAWKEYE'S FIGHT WITH CAP

In Captain America: The Winter Soldier, it isn't long before Steve Rogers finds himself in the middle of a conspiracy and on the run from S.H.I.E.L.D. After he escapes the Triskelion, we next see Steve in civilian garb, hiding in plain sight. But there was actually a reason Cap ditched his uniform in the script.

Although it was never filmed, there was supposed to be a scene where Alexander Pierce dispatches Hawkeye to go after Cap. However, Clint simply fakes a fight between him and his target, while letting Steve know that he's being tracked through his suit. Therefore, Cap was supposed to ditch his uniform thanks to a bit of help from Hawkeye. Instead, the archer wasn't in the film at all.

18 THOR SUMMONS LIGHTING FROM THE NINE REALMS

In Thor: The Dark World, the Convergence of the Nine Realms and the discovery of the Aether are what brought the Dark Elf Malekith out of his long sleep. The villain was ready to plunge the universe back into darkness, using the open portals of all realms to unleash the Aether into all of them at once.

To defeat him, Thor had some scientific help from his human friends Erik Selvig and Jane Foster. However, in the original script of the film, Thor was supposed to defeat Malekith on his own, by summoning lightning through the portals of all nine realms. This would have been so much cooler than what we got, and would have been a powerful showcase for the God of Thunder.

17 THE DESTRUCTION OF XANDAR

The opening of Avengers: Infinity War saw Thanos and his Black Order attack Thor's Asgardian ship. To the surprise of the audience, the Mad Titan was already in possession of the Power Stone, which was last seen on the planet Xandar at the end of the first Guardians of the Galaxy movie.

While everyone assumed that Thanos would obliterate the Nova Corps to get to the Power Stone, the MCU movies instead skipped over that scene. However, there was a version of the script of Infinity War that did open with Thanos' attack on Xandar. This would have shown the character's ruthlessness -- and not to mention that it could have also set up a possible solo Nova film.

16 STARK MENTIONS PROJECT GOLIATH

In Iron Man 2, fans might recall a scene where Tony Stark studies the old schematics of his father's Stark Expo to discover the hidden plans for a new element that could save his life. However, there is actually an extended version of that scene that features Tony ordering JARVIS to find out more information through S.H.I.E.L.D's files on Project Pegasus, G.O.L.I.A.T.H. and Exodus.

Of course, Project Pegasus would later be seen in 2012's The Avengers, as the facility that studies the power of the Tesseract. Plus, a mention of Project G.O.L.I.A.T.H. would have tied Iron Man 2 back to this year's Ant-Man and the Wasp, which brings the project back to the forefront. Then, the door would have been open for whatever Exodus might have been.

15 THOR'S EXTENDED VISION

In Avengers: Age of Ultron, Thor enlists the help of his friend Erik Selvig to find the Water of Sights and get answers about the vision Scarlet Witch gave him. In the film, Thor sees brief glimpses of the Infinity Stones, and that leads him to help create the Vision. However, there is an extended cut of the scene that features the Norns speaking through Thor.

The voice speaks directly to Selvig, while Thor tries to be the conduit. The Norns explain how the Avengers can hope to defeat Ultron (with a human sacrifice) and they also divulge more information about the Mind Stone inside Loki's staff, which is one of the “Infinity Six.”

14 ULTRON FORGES A VIBRANIUM BODY

In the trailers of Avengers: Age of Ultron, we saw brief glimpses of Ultron forging himself a smoldering new body. However, such a scene was never actually in the film. When the character first appears, he is made up of discarded parts of the Iron Legion and, next we see him, his full form is already established.

However, it would have been interesting to see how the character comes to forge his first body. The character is one that most fans agree could have used a bit more depth and villainy, and seeing how the recently born Ultron creates a body for himself, could have been what was needed to make Ultron a fan-favorite villain in the MCU.

13 STEVE ROGERS ADJUSTS TO MODERN TIMES

In 2012's The Avengers, there wasn't any time to waste. With Loki on the run and the Tesseract in his control, Nick Fury had to scramble to assemble the Avengers. When we first find Steve Rogers in the film, he is in the gym, getting ready for his next mission. However, that wasn't always the case.

There is actually a sequence of deleted scenes which features Steve Rogers adjusting to his life in modern times. He watches old videos about the war, checks out his old friends' closed files, visits New York and goes to a restaurant. These are small tidbits, but they would have helped show how Cap was alone before he found the Avengers.

12 KAECILIUS GETS SOME DEPTH

In 2016's Doctor Strange, the focus of the film was on Stephen Strange and his teacher, the Sorcerer Supreme. Kaecilius, the villain of the film, was a malevolent presence, but some agreed that the character didn't receive enough depth. Well, there are a few deleted scenes from the film that would have added to the mysticism of Kaecilius.

One of those scenes involves the villain talking to a priest about the Bible, as well as the notion of the afterlife, before ending his life. Then, another scene was filmed which showed how Kaecilius and his followers receive the power of Dormammu. These were small scenes, but they would have greatly changed our perception of the character.

11 THE GUARDIANS TEAM-UP WITH HOWARD THE DUCK

One of the biggest surprises of the first Guardians of the Galaxy was seeing Howard the Duck appear in the after-credits scene of the film. The character would later make a second brief cameo in Guardians of the Galaxy Vol. 2 – but nothing more than that. However, the character was actually supposed to come back in Avengers: Infinity War.

In one version of the script of the film, in his search for answers, Peter Quill was supposed to seek out Howard the Duck during an intergalactic poker game. The scene would have been brief, but the character would have actually served a story purpose beyond that of a cameo, something that could have led to more appearances down the road.

10 MALEKITH'S BACKSTORY

Thor: The Dark World doesn't rank at the top of any fan's favorite Marvel Cinematic Universe movie. In fact, even the star of the film himself, Chris Hemsworth, has recently said that the film was simply “meh” to him. One of the reasons the film didn't live up to usual Marvel standards is because the villain, Malekith, didn't receive much screen-time or depth.

However, there was a version of the script of the film that would have included a lot more Malekith. We were supposed to find out about the Dark Elk's family and his losses -- things that would have informed us of his hatred for Asgard and his need to plunge the universe back into darkness.

9 BUCKY WANTS A SHIELD OF HIS OWN

In Captain America: Civil War, Steve Rogers goes to war with Tony Stark in order to protect his friend Bucky Barnes. With a ticking clock, Stark doesn't have time for explanations, so the two's respective Avengers teams go to war. During the massive airport action scene, Avenger fights Avenger, and powers are showcased.

During that fight, there is actually a brief deleted scene that saw Bucky use Captain America's shield, and then express interest into getting one his own. While played for laughs, this scene could have also established the groundwork for Bucky taking on the mantle of Captain America if something happens to Steve, or if he chooses to step away from the uniform.

8 PETER'S FIELD TRIP IN WASHINGTON

In Spider-Man: Homecoming, Peter Parker and his debate team go to a special event in Washington, D.C – the city in which Captain America: The Winter Soldier took place. Well, in a deleted scene of the film, Peter's school bus drives by the remains of the Triskelion, which had been destroyed by falling Helicarriers in the Captain America sequel.

This scene would have shown the toll the big fights in the MCU take, while furthering the involvement of the clean-up crew known as Damage Control. Plus, it would have helped further cement the idea that Steve Rogers is now a fugitive from the law and on the run ever since the events of Captain America: Civil War.

7 BUCKY AND THE COMMANDOS ARE TAKEN PRISONER

In Captain America: The First Avenger, Steve Rogers' first mission is to go deep in Hydra-controlled territory and save his friend Bucky Barnes, as well as the rest of his company. However, there is actually a deleted scene from the film that shows how Bucky got captured by Hydra.

Not only that, the scene would have also introduced Dum Dum Dugan and the rest of the Howling Commandos much earlier in the film. This could have established Captain America's allies in a different manner, before he first meets them in the Hydra prison. Plus, the scene would have also shown the threat of Hydra's Tesseract-fuelled arsenal.

6 WHIPLASH FALLS AT THE HANDS OF WAR MACHINE

In Iron Man 2, Iron Man and War Machine both combine their powers to defeat Whiplash. But it's the villain's final attempt to destroy Tony Stark that ultimately leads to his end. However, there was a much different ending filmed for Iron Man 2, one that saw Whiplash survive this fight and later threaten the life of Pepper Potts.

Iron Man would have flown to her rescue, and it would have been War Machine who takes out Ivan Vanko permanently. This would have drastically altered the ending of the film, and it would have cemented War Machine as a hero in his own right. Perhaps then, the character's development would have been different as well.

5 THOR AND LOKI JOKE ABOUT THEIR HELMETS

The original Thor movie introduced the God of Thunder as he was walking towards his coronation as the new King of Asgard. However, there is a deleted scene from the film that introduces Thor prior to that, as he gets ready for his coronation. Loki is also in the scene, and the rivalry between the two, as well as their brotherly bond, is quickly established.

Not only that, the two make fun of each other's respective helmets, calling each other out on their feathered and cow looks. In retrospect, this introductory scene between the two brothers would have made for a great introduction to a complicated relationship that ended with Loki sacrificing himself to save his brother.

4 THE GRANDMASTER COMES TO EARTH

The after-credits scene of Thor: Ragnarok showed that the Grandmaster was now at the mercy of his own subjects on Sakaar. However, there was a much different scene filmed for the character's conclusion. Before it was changed, the Grandmaster was supposed to find himself aboard the Ark, the Asgardian ship led to Earth by Thor.

While that ultimately never happened, it would have considerably changed things. Could the Grandmaster have been able to face Thanos aboard the ship, or would he have escaped to find refuge on Earth? Knowing the Grandmaster, we certainly think he would have weaseled his way out, and then the question would have been what would the character be up to on Earth?

3 ARNIM ZOLA ESCAPES DESTRUCTION

Arnim Zola is an important villain in Captain America's rogues gallery. The character wasn't the main antagonist of The First Avenger, but he still had a noticeable presence, one that saw him make a return as a machine in modern times in The Winter Soldier. Sadly, the character was destroyed by an explosion.

However, there was a version of the script of the film that featured Zola's screen detach from the console and run out on mechanical legs before the warehouse could be destroyed. Zola's survival could have ensured the character's return in Captain America: Civil War, where he could even have appeared as an ally to Zemo.

2 VISION FIGHTS THE AVENGERS

When the Vision is born in Avengers: Age of Ultron, he is thrown by Thor towards a window, and then joins the Avengers. However, there was an entire action scene filmed that saw Vision fight the Avengers following his birth. The character goes up against Thor, Captain America and Iron Man, and showcases his powers.

This scene would have been useful in showing the audience Vision's skill set from the get-go. They would have instantly known that he can fly, phase through solid objects, fire a powerful laser beam, and hold his own against the might of Thor. Furthermore, this was the scene that explained why Vision formed an armor and cape: in order to match Thor in combat.

1 CAPTAIN MARVEL IS A NEW AVENGER

Avengers: Age of Ultron ends with Captain America and Black Widow walking towards the latest recruits of the New Avengers: Scarlet Witch, Falcon, War Machine and Vision. These characters were all seen in the film, in big or small roles, something which helped make sense of their presence on the roster at the end of the film.

However, there was a time when Captain Marvel was supposed to be introduced in that final scene. The character was meant to be a surprise addition, and her start in Phase 2 of Marvel's movies would have greatly altered the plans of Phase 3. There is simply no telling what Civil War and Avengers 3 would have looked like with someone as powerful as Captain Marvel in the MCU.