For the last ten years, the MCU has been ramping up to the giant event that was Avengers: Infinity War, no more so than in the third phase of its films. Phase three of the MCU saw many storylines finally converging and a lot of questions being answered. Each film in the third phase of the MCU had the task of building up to Infinity War (and in some cases, showing the aftermath), while also telling their own individual stories. The immense work and talent that went into making these films paid off in big ways, and saw the characters that audiences love changing, growing, and becoming more dynamic. Behind the scenes of all of these films were some interesting, and in some cases, challenging decisions made by the filmmakers and cast members.

These events that took place behind the scenes ultimately helped to shape the MCU's third phase into what it became, and in many ways they informed the storytelling and the feel of each film. More than ever, the MCU relied on cohesive storytelling from a number of different directors working on each film in order to have the individual stories coalesce into the biggest film event of the year. Considering the epic scope of this phase of films, the behind the scenes decisions, and the antics of all the people involved in the films, these turned out to be some of the most ambitious films in the MCU. These are 20 behind the scenes facts about the third phase of the Marvel Cinematic Universe.

19 SEBASTIAN STAN TAUNTED ROBERT DOWNEY JR.

Bucky Barnes fighting Iron Man

Captain America: Civil War brought together almost all of the Avengers (plus a couple of new faces) to engage in one of the biggest battles in MCU history. Not only was the airport fight one of the most ambitious sequences in the entire collection of MCU films, it also gave all of the heroes a chance to show off their moves.

This meant that some actors who had not yet worked together would be filming fight scenes, including Robert Downey Jr. and Sebastian Stan. The day before they were to shoot their scene together, Stan sent Downey Jr. a video of him doing some intense bicep curls with Iron Man's helmet in front of him. He included the message, "Looking forward to working with you tomorrow, Robert."

18 CHRIS EVANS WORE T-SHIRTS THAT WERE TOO SMALL

Chris Evans in Civil War

If there's one thing that was truly impressive in Civil War, it wasn't the special effects, or the introduction of Spider-Man, or even the scope of the story. It was Chris Evans's biceps in the scene where he attempts to stop a helicopter from taking off. Not a single person could say they weren't impressed by that scene.

As it turns out, costume designer Judianna Makovsky was instructed to put Chris Evans in shirts that were at least a couple sizes too small for him. This was done in order to help his muscles really show up on screen. Clearly the strategy worked, because those muscles definitely popped, no CGI required.

17 DAN HARMON WAS A SCRIPT CONSULTANT

Dan Harmon

Writing a script, particularly for a big Hollywood movie like the ones in phase three of the MCU, often requires the input of several writers to get the story, characters, and pacing just right. As it turns out, one of the uncredited contributors on Dr. Strange happened to be Community and Rick and Morty creator Dan Harmon.

Harmon was brought on to consult on the script by director Scott Derrickson, who said that Harmon contributed greatly to the final product, even though most of the jokes he wrote wound up on the cutting room floor. In an interview with Moviefone, Derrickson said that Harmon's jokes were too strange, but that he was able to provide a "really striking analysis" of the script overall.

16 JOAQUIN PHOENIX ALMOST PLAYED DR. STRANGE

Joaquin Phoenix

Benedict Cumberbatch was a pretty great pick to play Dr. Strange, and he has proven that he fits into the MCU very well. However, the character might have been radically different if the studio had wound up casting one of their other choices for the role: Joaquin Phoenix.

Cumberbatch originally turned down the role due to scheduling conflicts with his theatre work in Hamlet. Phoenix was the second choice, and negotiations were apparently underway. However, Phoenix ended up turning down the role, saying he did not want to commit to a multi-picture deal. Although Phoenix eventually got his chance to play an indelible comic book character, being cast as the lead in Todd Philips's Joker movie.

15 JAMES GUNN PERFORMED BABY GROOT'S DANCE IN GUARDIANS  2

Groot in GOTG2

One of the most memorable scenes in Guardians of the Galaxy Vol. 2 comes right at the beginning. While most of the Guardians are busy battling an interdimensional monster, Baby Groot takes the opportunity to bust a move to the grooving sounds of ELO's "Mr. Blue Sky." The sequence is a great exercise in contrast. The joyfulness of the music and the cuteness of Groot's dancing are juxtaposed with the chaos happening in the background.

The adorable dance sequence was actually the work of director James Gunn, who performed the dance moves which were then motion captured and used as the model for the dance sequence.

14 VIN DIESEL HAD A SPECIAL GROOT SCRIPT

Vin diesel and Baby Groot

Though he only ever says the words "I am Groot," Groot is given a wide range of emotions and intonations in those lines. This is due to the excellent voicework done by Vin Diesel, who also performs his lines in 16 different languages. However, to get the inflection and the context of those three words just right, Diesel needed to know what Groot was trying to express.

That's why James Gunn had a special script written just for Diesel, where all of his lines as Groot are written out in plain English. This is how Diesel was able to capture the perfect intonation of everything he said as the character. Vin was also able to do the baby Groot voice with very little audio processing.

13 THE HOMECOMING CAST HAD A JOHN HUGHES MARATHON

Spider-Man Homecoming cast

Spider-Man: Homecoming  did a lot of heavy lifting to reboot the superhero franchise and make it fresh. One of the key factors in this third installment of the superhero is that the film takes place squarely during Peter Parker's high school years. The director, Jon Watts, turned to John Hughes, the master of the teen movie, for inspiration.

The cast had the opportunity to watch a marathon of John Hughes movies to truly get the feel for what it's like to be a teenager, and what it means for their characters. Tom Holland told Popsugar UK "we basically just all sat down in my house in Atlanta, all the cast, and we just watched them all in one day and just had like a Dominos day. It was amazing."

12 HOMECOMING HAS A FREAKS AND GEEKS PEDIGREE

Martin Starr in Spider-Man Homecoming

Aside from the influence from John Hughes films, Spider-Man: Homecoming also gets a boost of teenage cred from its connections to Freaks and Geeks. The Judd Apatow created show starred Martin Starr and John Francis Daley as two of the titular geeks, and both of them had their hands in the making of the film.

Martin Starr played Mr. Harrington, the teacher and coach of the academic decathlon team, while John Francis Daley had an offscreen role as one of the main screenwriters. Both of their characters on Freaks and Geeks would probably be proud to know that their future selves were involved with a Spider-Man movie.

11 TOM HOLLAND NAPPING

Spider-Man Homecoming poster

The original promotional poster for Spider-Man: Homecoming instantly captured the feel of the movie: a young, inexperienced Spider-Man, who, like any teenager, sometimes just needs to hang out and listen to some music. However, the shoot, which let everyone know that this was going to be a vastly different Spider-Man movie, wasn't planned at all.

It turned out that Tom Holland was simply taking a nap during a break in filming. The on-set photographer captured that candid moment of Holland listening to some tunes in full costume. Holland later said "I was just asleep on the floor, and the photographer took a picture. So when they made that the poster, I was like ‘What! What the hell, guys!’"

10 SKURGE WAS USING THE DIRECTOR'S SHAKE WEIGHT

Skurge's Shake Weight

Thor: Ragnarok did something that most people would think was impossible: it made the Thor films interesting and engaging again. The film, which took a lot of inspiration from late '70s and early '80s sci-fi like Flash Gordon, also had something that the earlier Thor movies failed to utilize effectively: a sense of humor.

For example, when Skurge, played by Karl Urban, is showing off his collection of items gathered from around the universe, one of the objects he is shown using is the embarrassingly ridiculous shake weight. That shake weight actually belonged to the film's director, Taika Waititi, who bought it when he was in Green Lantern.

9 THOR: RAGNAROK WAS 80% IMPROVISED

Chris Hemsworth in Thor Ragnarok

Thor: Ragnarok was the final step in turning Thor, son of Odin, the God of Thunder, into a total goofball, and the shift in tone actually worked perfectly. When compared with the almost Shakespearian tone of the first Thor film, there is a marked difference and an overall improvement in the writing.

Except that most of the film's humor wasn't even on the page, as director Taika Waititi stated "I would say we improvised probably 80 percent of the film, or ad-libbed and threw in stuff." The strategy definitely paid off, as Thor: Ragnarok was easily one of the funniest films in the MCU, and was a light-hearted adventure in heavy contrast to Infinity War.

8 WAKANDANS ARE SPEAKING A REAL LANGUAGE

Cast of Black Panther

Black Panther was a huge hit with critics and audiences, and it was easy to see why. The cultural influences present throughout the film helped to shape Wakanda into a distinct nation, with its own history and identity. Part of that had to do with the language spoken in Wakanda, which happens to be a real South African language.

Xhosa, the Buntu language spoken by the cast, uses click consonants, and was apparently very hard to learn. The idea of using Xhosa as the Wakandan language originated with actor John Kani, who played T'Challa's father T'Chaka. It was his idea to speak Xhose during his appearance in Civil War. Luckily, Chadwick Boseman also knew the language, and the MCU just took it from there.

7 JOHN BOYEGA WAS CONSIDERED FOR A ROLE IN BLACK PANTHER

John Boyega in Pacific Rim Uprising

Starring as Finn in the new Star Wars films has helped to put John Boyega on the map, leading him to some other ambitious roles in films like Pacific Rim: Uprising and Detroit. However, the star was also considered to cross over from one Disney property to another, as rumors circulated in 2016 that he would join the cast of Black Panther.

However, Boyega squashed those rumors, and has also said that he had no plans on being in the eventual Black Panther sequel. However, in April of this year, Boyega said that he had taken meetings with Marvel, but did not reveal any information about the role he may play in the future.

6 TOBIAS FUNKE'S CAMEO IN INFINITY WAR

Tobias Funke in Infinity War

Avengers: Infinity War was an epic, sweeping story that spanned every corner of the Marvel Cinematic Universe, including space. In one scene, Gamora and Star-Lord encounter Thanos on Knowhere, where the mad Titan uses the reality stone to trick them. However, before the reveal that Knowhere is destroyed, the audience gets to see one of the collector's items.

That item happens to look a lot like Tobias Funke from Arrested Development, painted blue and wearing his signature jean shorts. The Russo Brothers even tried to get David Cross to reprise his role for the quick cameo, but unfortunately the actor was working in London and couldn't make it back for filming.

5 GROOT'S TRAGIC FINAL WORDS

Groot in Infinity War

Audiences were left in shock at the end of Avengers: Infinity War when Thanos finally achieved his goal of wiping out half of all life in the universe. The emotional reaction to watching half of the MCU's heroes fade into dust was palpable. One of the heroes that faded away after the snap was Groot, who was able to utter one last "I am Groot" to Rocket before disappearing.

That moment was heartbreaking enough as it was, but it was made even worse by a revelation from James Gunn on Twitter. When a fan asked him if he knew what Groot's final words translated to, he simply replied "Dad."

4 PEYTON REED WAS INSPIRED BY ELMORE LEONARD

Paul Rudd and Evangeline Lilly

After the devastation of Infinity War, audiences were treated to the further adventures of Scott Lang and the gang in Ant-Man and the Wasp. The film was a light, breezy, crime caper that acted as a nice palate cleanser. The film continued to utilize the witty banter and quick-witted back and forth conversations that made the first Ant-Man film so fun.

Director Peyton Reed has said that he drew inspiration for the film from the crime novels of Elmore Leonard, which include Get Shorty and Rum Punch, the novel that served as the basis for Quentin Tarantino's Jackie Brown. Reed told Slash Film he wanted the film to have "street level criminals and more powerful antagonists, and then random situations where the plan gets screwed up constantly."

3 MICHAEL DOUGLAS AND MICHELLE PFEIFFER

Michael Douglas and Michelle Pfeiffer

Ant-Man and the Wasp features the return of Michael Douglas as Hank Pym, but also stars Michelle Pfeiffer as the long lost Janet Van Dyne. These two actors both have long and celebrated film careers, however despite the fact that both of them have been acting since the '80s, they have never appeared in a film together.

Speaking with CinemaBlend, Douglas said he was excited to have the opportunity to work with Pfeiffer. He also added that he was looking forward to working with Laurence Fishburne, another actor who despite having a long career, has never appeared in a film with Michael Douglas. Douglas told Cinemablend "That's one of the joys of these pictures, is that you're always surprised with the new talent that they bring in."

2 JUDE LAW GOT ADVICE FROM ROBERT DOWNEY JR.

Jude Law and Brie Larson in Captain Marvel

Several actors are making their MCU debut in the upcoming Captain Marvel, including Jude Law. Law has been reported as playing Mar-Vell, however details of his role are still being kept under wraps. The actor knew that coming into the MCU was going to be a big deal, so he sought advice from a good source: Robert Downey Jr.

Law told Entertainment Weekly that the Iron Man actor told him that being in a Marvel film is about "fitting this one piece into a bigger picture," and that "It’s not about trying to understand everything. Just do your piece." That's pretty good advice from someone who has been in the MCU since the very beginning.

1 CAPTAIN MARVEL IS THE FIRST MCU FILM WITH A FEMALE DIRECTOR

Brie Larson as Captain Marvel

Despite the fact that the MCU has 20 films in its entire collection, there have been none that were directed by women. However, that is going to change with the release of Captain Marvel next year, which is being directed by Anna Boden and Ryan Fleck.

Boden and Fleck have never taken on a blockbuster film, however their previous collaborations including the Oscar nominated Half Nelson and It's Kind of a Funny Story were met with critical acclaim. In an interview with Fandango, Kevin Feige said of the duo "when you look at the work that Ryan and Anna have done in the past, they are all amazing and very diverse character studies and journeys, and that impressed us."