When it comes to movie-making, what audiences see in the final version of any given production is very rarely the full extent of what was actually filmed. Editors often have to cut certain scenes from movies - whether it be for some overarching artistic purposes, or simply because including them would make the movie in question too long.
The most popular movies in the Marvel Cinematic Universe are no different. In fact, it has recently been stated that Avengers: Age of Ultron (141 minutes long) could have been anything up to 165 minutes long, while the upcoming Ant-Man (which is expected to be around 140 minutes long) could have been anything up to 180 minutes long, had every fully-filmed scene been included in the cinematic releases.
Of course, no deleted scenes from those latter movies have made their way to the internet yet (Age of Ultron's trailers had some brief clips in them that didn't make the final version of the movie, but we don't know the full extent of those scenes, and Ant-Man isn't actually out yet), but the previous ten movies in the MCU have all seen deleted scenes go public some time after their release.
The following are the ten best - whether it be because they're extra funny, interesting or because they were actually quite important - that didn't make it into the final versions of Marvel Cinematic Universe movies. The clips in question are attached, for your viewing pleasure.
10 The Basketball Court (Captain America: The Winter Soldier)
In 2014's Captain America: The Winter Soldier, Captain America became a fugitive from S.H.I.E.L.D. (or, at least, the HYDRA agents who had infiltrated S.H.I.E.L.D.) after he withheld information from them regarding what Nick Fury had told him earlier in the film.
In the movie, the next time audiences see Captain America is in a hospital, wearing a hooded top. However, a deleted scene shows where he acquired it.
The hero is tracked by S.H.I.E.L.D./HYDRA to a basketball court, where a group of armed agents burst in, only to find a sports bag with Captain America's uniform inside it. It seems he had purposely been seen there in order to draw them there, only to escape in secret wearing the clothes that were in the bag.
9 Trevor's Accents (Iron Man 3)
A deleted scene from 2013's Iron Man 3 occurred when Tony Stark and James Rhodes infiltrated the mansion in which Trevor Slattery was hiding.
In this particular scene - which is both funny and demonstrative of Sir Ben Kingsley's incredible acting skills - a guard attempts to contact another already immobilised guard by radio, in order to check on the status of the heroic intruders.
Because the immobilised guard can't reply, Stark and Rhodes have Slattery - an actor - use his abilities to pretend to be the immobilised guard, by using a Russian accent, to tell the guy on the other end that the intruders have been apprehended. Impressed, the heroic pair then have him bust out a number of other accents, including Irish and Spanish.
8 The Malfunctioning Light (Guardians Of The Galaxy)
In this deleted scene from 2014's Guardians of the Galaxy, Nova Corps members Rhomann Dey and Denarian Saal have an altercation about where the captured titular misfits should be held captive.
Dey insists that a local prison will do the job, but Saal is insistent that only the intergalactic prison known as the Kyln will be sufficient - though Dey believes it's too hostile and vicious a place for them. Saal is the superior officer, so they end up in the Kyln (as we find out in the movie itself, of course).
This scene is broken up by Saal humorously helping Dey to fix a broken light on the front of his Nova Corps uniform.
7 Gamora & Nebula's Altercation (Guardians Of The Galaxy)
Although adoptive sisters Gamora and Nebula did speak briefly to each other in 2014's Guardians of the Galaxy - and indeed have a fairly extensive one-on-one fight with each other - most of their hostility was displayed through body language and evil looks towards each other, but a deleted scene showed them doing a little bit more of all of those things.
Nebula angrily complains about how Thanos sees her as inferior to Gamora, even though she believes she isn't, while Gamora initially tries to calm the situation down.
However, they do have something of a physical altercation - albeit a rather subdued one - before Gamora ultimately walks off.
6 Black Widow Talks To Nick Fury (Captain America: The Winter Soldier)
In 2014's Captain America: The Winter Soldier, after Nick Fury had faked his own death and reunited with Black Widow, Maria Hill and Captain America to help the latter evade S.H.I.E.L.D./HYDRA, a deleted scene shows a discussion between him and Black Widow.
In the discussion, Black Widow says Fury should have kept her informed that he wasn't really dead - proving that she cared for him and opening up for one of the first times on film (although we've since seen her open up much more emotionally in Avengers: Age of Ultron).
Fury said he had to make his death seem real and Black Widow ultimately agreed with him, saying she'd have done the same thing, but it really showed a vulnerable side to the usually hard-faced former assassin.
5 The Extended Scene After Hulk's Fall (The Avengers)
This deleted scene from 2012's The Avengers is actually an extended version of a scene that did make the final movie. After Hulk fell from the S.H.I.E.L.D. Helicarrier, he landed in some kind of disused facility and encountered Harry Dean Stanton as a security guard.
The portion of the scene that made the final cut saw Stanton (who is known for his part in 1979's Alien) asking Bruce Banner if he was an alien, given that he'd fallen from the sky.
The deleted scene is more poignant, as it has Stanton asking Banner if he was a big guy who turned into a little guy or vice versa - and Banner wasn't sure how to answer. Banner then says he knows where he can do the most good (New York, in the fight against the Chitauri), but it's also where he can do the most harm. Stanton simply replies that's something that makes him no different to anyone else.
4 Loki & The Other Talk Some More (The Avengers)
A deleted scene from 2012's The Avengers (and one that hasn't even had its special effects completed in this clip) shows Loki having another chat with the Chitauri commander known as The Other during the final battle in New York.
In the clip, Loki complains that the Chitauri lack finesse, while The Other claims they will be happy to sacrifice their lives to defeat the Avengers. The Other then suggests to Loki that he uses the power of the sceptre to gain the upper hand in the battle.
Unfortunately for Loki, it's at this point that he realises he had dropped it during his fight with Thor atop of Stark Tower.
3 Thor Vs Asgardian Guards (Thor: The Dark World)
Thor: The Dark World saw Jane Foster taken to Asgard, after having become host to the Aether, where she was in Odin's custody for the purpose of what the All-Father believed to be everyone's safety.
However, Thor wanted to take her - along with Loki - to Svartalfheim in order to trick Malekith into drawing the Aether out of her, but Asgard's forces tried to stop him.
In this deleted scene, Thor drops his hammer as several guards approach him - prompting Loki to mock him - but Thor insists he only wants to immobilise them, not kill them, and manages to do so with his bare hands alone.
2 Captain America Readjusts (The Avengers)
Captain America's reintroduction to the world in 2012's The Avengers really seemed quite rushed - but that could have been quite different, had this deleted scene been included in the final movie.
It shows the super soldier catching up with what happened in the war, what has happened to those he knew and loved (which somewhat set up the events in the Winter Soldier), and trying to get back out into the world (including being encouraged to ask a waitress for her phone number by a cameoing Stan Lee).
It also shows him travelling on a train and signing up to join the gym in which audiences see him when he first appears in the final movie.
1 The Alternate Opening (The Incredible Hulk)
An alternate opening to 2008's The Incredible Hulk sees Bruce Banner in the Arctic. While there, he attempts to shoot himself to rid himself and the world of the burden of the Hulk. Unfortunately for him, the Hulk doesn't take too kindly to the attempt and he simply spits the bullet back out - frustrating Banner and emphasising just how hard to kill his big green alter-ego is. This scene is actually referenced in 2012's Avengers movie.
In this scene, eagle-eyed viewers have also noticed that Captain America's shield can be seen briefly under the ice - foreshadowing the super soldier's discovery and de-icing in the aforementioned Avengers movie.