There’s no stopping Marvel’s box office dominance, with each new hero, star, character, or superteam adding to the universe’s legacy - and behind the scenes, adding even more unbelievable stories and coincidences. But for all its success and seemingly - perfect planning, the MCU has just as many weird, or hard to believe secrets that the studio would rather fans not spend time thinking about. Here are 20 Secrets the MCU Doesn’t Want You To Know.

Wolverine’s Cameo

Before the MCU became a blockbuster monster, the studio was a lot more open to sharing their universe with the rest of Marvel’s heroes at rival studios. It’s long been rumored that Marvel had considered having Hugh Jackman appear as his immortal clawed soldier alongside Cap during World War 2. Even if rights meant he couldn’t be CALLED Wolverine, it still would have been an incredible cameo.

Casting Iron Man

He may have become the face of the Marvel Universe, but when the role of Iron Man was being cast, the studio couldn’t have been less convinced Robert Downey Jr. was their man. While they would still have preferred Tom Cruise, director Jon Favreau knew Downey could pull off a brilliant man who realizes he’d been wasting his life - since he already had himself.

JARVIS

After years playing the voice of Tony Stark’s AI JARVIS, fans finally got to see actor Paul Bettany on screen, as the new Avenger, Vision. But it was a first for his costars, too. The actor admitted that he had never worked with Robert Downey Jr before then, having spent close to a decade just recording his lines in a studio after filming had wrapped.

Sam Rockwell’s Role

Iron Man 2 takes a beating from fans, but not it’s villain. But in a parallel universe, Robert Downey Jr and Sam Rockwell could have had their roles reversed. Rockwell was invited to read for the hero, and was apparently in the running before Downey was cast. His audition clearly impressed, since he was asked to return for the sequel.

Daredevil’s Powers

Since Daredevil is as serious a Hero as they come, Marvel doesn’t advertise the fact that the chemicals which gave him his powers also turned a group of turtles into teenage mutant ninjas. That’s according to the turtles creators, who mirrored most of Daredevil’s story in their own, with Splinter a play on Stick (Matt’s mentor) and fighting the veil ninjas of the Foot, instead of Marvel’s Hand.

Hulk’s Origin Story

With the Avengers’ success, fans everywhere are demanding more Hulk - but they almost had it. When Edward Norton signed on to play the hero, he rewrote the script, adding a longer origin and even more character scenes. He and the director tried to convince Marvel that it was the right move, but the studio thought tighter action was a better move. Either way, The Avengers gave some credit, revealing Bruce Banner had attempted suicide - the very first scene in Norton’s screenplay.

Iron Man’s Price Tag

Cap was a hit, but when The Avengers came along, Iron Man was Marvel’s biggest star - and Robert Downey Jr, and his agent, knew it. With just two movies under his belt, the actor negotiated a $50 Million paycheck for the team up, and Marvel had no choice but to pay. Since the movie made over a billion dollars, it was more than worth it.

Robert Banner?

He goes by Bruce, but officially, the Hulk’s alter ego is named Dr. Robert Bruce Banner. Why does he go by his middle name? Easy: writer Stan Lee forgot which one to use. The three part name was his cover story, but the Marvel legend later admitted he went months referring to Banner as Bob, before realizing his mistake.

Casting The God Of Thunder

When Marvel was looking to cast it’s riskiest Avenger, the god of Thunder, it came down to three actors: Tom Hiddleston, Chris Hemsworth, and his brother, Liam. Hiddleston got Loki and Chris got the lead, but weirdly enough, he found out he got the role while on the set of Cabin in the Woods, with his future Avengers director, Joss Whedon. Just days before, Whedon had actually claimed he’d make a perfect Captain America.

Odin’s Secret

The Dark World offered one of the first lessons in the Infinity Stones of the MCU, courtesy of Odin, Thor’s dad. But the Allfather was apparently keeping some secrets. According to Thor director Kenneth Brannagh, it was Odin who put the MCU in motion, hiding the Tesseract in Captain America, the Infinity Gauntlet, and so on. Whether the current writers agree… We’ll have to wait and see.

Human Torch Costume

The mannequin wearing the original Human Torch costume in Captain America’s opening scenes is usually taken as a playful jab at star Chris Evans’ former role - but the truth is even crazier. The red suited Torch was actually the first Marvel superhero, whose name and powers were later recycled for the Fantastic Four - exactly like Evans, whose likeness and star quality got him recycled into the Avengers. What are the odds?

The Hulk Re-casting

When the role of Bruce Banner had to be recast for The Avengers, director Joss Whedon thought Marvel would have doubts about his top pick, Mark Ruffalo, since he wasn’t exactly an A-Lister at the time. To his surprise, he was Marvel’s top pick too, after he’d been on the shortlist before Ed Norton landed the part. Considering how that story played out, they probably wished they’d made that choice years earlier.

Post-Credit Secrets

Marvel is famous for its post credits scenes, but they’re not always easy to film, especially if they haven’t been written until after shooting is finished. For Thor 2, Natalie Portman wasn’t even available to film her post credits kiss as Dr. Jane Foster. Since she was the same size, Chris Hemsworth’s wife, actress Elsa Pataky (“PAD-eck-EE”) threw on a wig and stepped in to take her place.

Department H

The Marvel writers couldn’t help but make reference to the secret Canadian organization called Department H, mentioned in both The Winter Soldier and Agents of SHIELD. There’s one problem: thats the experimental agency that launched the Weapon X program which created Wolverine and Deadpool in the comics. Both characters to which Marvel no longer holds the rights. Let’s hope Fox didn’t notice.

Re-using Locations

The Marvel Universe crosses time and space, but the actual filming locations can’t. So the studio hopes fans won’t look too closely, or else they’ll notice that the centuries-old village in Thor’s prologue is the same one Red Skull attacks in Captain America. Or that the secret bunker where Bucky is brainwashed in the Winter Soldier is the same bank Cap is blown out of in The Avengers.

Sebastian The Sidekick

Since Captain America has passed his shield to a few successors in the comics, it’s no surprise that the Marvel films have established a few candidates in his friends Sam Wilson and Bucky Barnes. What fans don’t know is that actor Sebastian Stan was in the running for the role to begin with, until Chris Evans agreed to sign on, and Stan got his sidekick instead.

Iron Man’s Suit

It seems like a dream come true to wear the Iron Man armor, but the reality of a suit of armor isn’t as glamorous. Thanks to advances in CG, Robert Downey Jr. only has to wear a headpiece or shoulder pads on set. Whenever the iron Avenger’s face isn’t visible, fans are actually watching a digital creation, or a stunt man. Sorry to burst the bubble.

Laura Haddock

It’s an ironclad rule that no actor can play two different characters in the MCU, with Paul Bettany’s shift from JARVIS to Vision the only exception. Well, unless you count actress Laura Haddock, who appears in Captain America looking for an autograph… and again, as Peter Quill’s dying mother. The studio has denied any connection between the roles, making her casting… impossible to explain.

Guardians On A Budget

Guardians of the Galaxy turned out to be one of Marvel’s biggest hits - but they didn’t expect it to be. In fact, the studio only agreed to pay for the movie’s massive prison set to be built once a plan was set to melt down the steel after filming wrapped, so it could be sold for scrap to gain back the money spent. We doubt that will be a problem for the sequel.

Casting Cap

These days, almost every young actor is fighting to play a superhero and hit blockbuster level. But when Marvel sought out actor Chris Evans to play Captain America, he wasn’t sold. With terrible memories of his Fantastic Four contract, Evans actually turned Marvel down - THREE times. He finally agreed when Marvel dropped his initial contract from 9 movies to 6, and the rest is history.