It goes without saying that the MCU is the biggest thing in movies today. The ground-breaking cinematic universe had a massive impact on modern cinema and spawned many imitators. After over ten years, 23 films and the biggest movie of all time, this massive franchise only looks to be getting bigger.

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With the immense popularity of the film and their connected nature, fans pour over every frame of the movies to see what new revelations they can uncover. However, some of the most interesting behind-the-scenes facts can only come from the filmmakers themselves. Here are some of the hidden details of the MCU that you would only know from listening to the commentary.

Hawkeye's Family — Avengers: Endgame

Avengers Endgame Hawkeye Trains Daughter

Avengers: Infinity War ended with the gut-punch of seeing many of our favorite heroes evaporate into dust following Thanos' snap. Avengers: Endgame didn't let us off any easier with its first scene. As we catch up with Hawkeye, he is enjoying a day with his family when they all suddenly vanish, leaving him alone.

As effective as that moment was to open the film, it was almost used as the final scene in Infinity War. Honestly, that might have been an even bigger blow, as we had not seen Hawkeye the entire film and this would have been a brutal note to end on.

Hemsworth's Audition Process — Thor

Thor and Loki look up in Thor.

It's hard to imagine anymore other than Chris Hemsworth in the role of Thor. However, his path to getting the part was not easy.

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On the Thor commentary, director Kenneth Branagh recalls the unsuccessful audition process with Hemsworth. When he was first brought in for the role, Hemsworth was sick, there were no pages for the script and it was decided he wasn't right for the role. After several months and a more developed character, a producer decided to bring Hemsworth back and he convinced them he was their Thor.

Steve Rogers = Rocky Balboa — Captain America: The Winter Soldier

Bucky Barnes Punching Steve Roger's Shield in Captain America: The Winter Soldier (2014)

Captain America: The Winter Soldier was a very new take on the titular character. The filmmakers decided to style the film after the conspiracy and political thrillers of the '70s. But when it came to Cap himself, they picked another iconic cinematic hero as their template.

The Russo brothers and the film's writers explain that they based Steve Rogers in the sequel after Rocky Balboa. They saw Steve as a good and honest man who nonetheless refuses to give up the fight. They said this also inspired them to let Cap take a few beatings in the film.

The Real Mandarin — Iron Man 3

Aldrich Killian powered up in Iron Man 3

Iron Man 3 features one of the most controversial villains in the MCU. After teasing the existence of the Mandarin, a classic Iron Man foe, it is revealed the man is nothing but an actor. Fans were disappointed they didn't get to see the true Mandarin in the film, however, the filmmakers disagree.

According to Shane Black, the idea to have Aldrich Killian reemerge at the end of the film was so that he could let the audience know that he was the real Mandarin the whole time. Despite Black's insistence, Marvel seems to disagree and will be introducing the real Mandarin in Shang-Chi.

Controversial Casting — Doctor Strange

Tilda Swinton as the Ancient One in Doctor Strange

The MCU has done a pretty good job of avoiding controversy over the years, but one particular bit of casting did catch some heat. In Doctor Strange, Tilda Swinton was hired to play the Ancient One, a character who was traditionally an Asian man in the comics. Some called this casting "white-washing."

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To director Scott Derrickson's credit, he makes a point of bringing up the issue himself. He maintains that there were no racist tendencies behind the choice, and the casting was actually meant to subvert the racist stereotypes of the character which were present in the comics.

Yondu's Death — Guardians Of The Galaxy Vol. 2

One of the most heartbreaking deaths in the MCU has been Yondu's sacrifice in Guardians of the Galaxy Vol. 2. After saving Quill, Yondu gives his surrogate son his spacesuit and flies him to safety as he dies in the coldness of space.

Though the moment is very effective, writer-director James Gunn was rather hesitant to put it in the film for one very touching reason. As he explains, actor Michael Rooker has been in every one of Gunn's films and is a close friend. The thought of doing Guardians of the Galaxy Vol. 3 without Rooker was not easy.

Steve Knew — Captain America: Civil War

captain america civil war mcu secret identity

Though the initial conflict at the center of Captain America: Civil War was the Accords, the real fight comes down to something much more personal' Zemo's real plan was to expose the truth that Bucky Barnes was the one who killed Tony Stark's parents, and Steve Rogers knew.

According to the filmmakers, the revelation that Steve knew was something they struggled with. They thought that such an omission would be out of character for the noble hero. Ultimately, they decided it worked because he would make those tough choices to protect Bucky.

The Wakanda Bible — Black Panther

Black Panther was not only one of the MCU's biggest films, but it also made history becoming the first superhero movie to be nominated for Best Picture at the Oscars. A big part of the film's acclaim was the amazing and detailed representation of the Wakandan culture.

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In order to make the country, its people and its history feel as real as possible, a massive "Wakanda Bible" was made. The 515-page document explored all aspects of Wakandan life, which the filmmakers could use as a reference point throughout production.

Tony Stark The Villain — Avengers: Age of Ultron

Age of Ultron Tony Stark

Avengers: Age of Ultron didn't get the warmest response when it was released, but in the wake of Infinity War and Endgame, it does give an interesting glimpse into Tony Stark's character motivations. We see Stark convinced a greater threat is lurking in the cosmos, and he uses Loki's scepter to create Ultron as a way of protecting Earth.

In Joss Whedon's mind, this decision by Stark was not just a well-intentioned mistake. For the sequel, Whedon viewed Stark as the villain of the story and the biggest threat facing the Avengers.

The Funeral Scene — Avengers: Endgame

Avengers Endgame Iron Man Tony Stark Death Robert Downey Jr

Avengers: Endgame saw many of our favorite characters moving on, including the devastating death of Tony Stark. After sacrificing himself to destroy Thanos and his arm, Tony succumbs to his wounds and dies.

What follows is a moving scene in which virtually every MCU star appears on screen together at Stark's funeral. Remarkably, there is no camera trickery or digital manipulation in the scene. All those actors did really come together to film that pivotal scene, though they were all told it would be a wedding scene. The Russo brothers called it the most complicated shoot to schedule in film history.

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