The Marvel Cinematic Universe is officially 10-years-old. Iron Man was released on May 2, 2008, and thus, the MCU was born. The universe of interconnected movies has evolved immensely since then, but given what fans all around the world have just experienced with Avengers: Infinity War, it's worth acknowledging the relatively humble beginnings of this epic, groundbreaking and wildly successful cinematic experiment. In the decade since the release of Iron Man, the MCU has turned into a universe-sprawling, massive franchise that everyone in Hollywood wants to emulate.

Iron Man, at the time of its release a decade ago, centered on a character that was in no way familiar to those in the mainstream. Though Tony Stark had been a core member of The Avengers in the world of Marvel Comics since the 60s, those who didn't religiously read comic books really weren't too familiar with the character, beyond perhaps a passing familiarity of the name. But since many of the Marvel characters had been licensed to other studios years prior, Marvel Studios had to make due with what they had.

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Not only was Iron Man a character not many knew prior to the movie, but the casting of Robert Downey Jr., at the time, was tremendously risky. It's easy to forget now, and many who grew up with the MCU may not even know, but Downey was not at what one would call a high point in his career at that time. After some scandalous happenings, RDJ wasn't the big star he once was. However, he was perfect for the role of Tony Stark and, to date, it's hard to think of a superhero who was more perfectly cast. Not only that, but Jon Favreau wasn't experienced with blockbuster filmmaking at the time. There was a lot working against this movie.

Yet, Iron Man wound up being a smash success. The movie grossed $585 million worldwide and was a huge hit with critics and fans alike. It's still the second-highest rated MCU movie on Rotten Tomatoes with a rock-solid 94 percent approval rating. Black Panther is the only movie higher, so up until very recently the first Iron Man was still the king of the hill, so to speak. Without Iron Man succeeding in such a way, the MCU as we know it may not exist. And Disney may not have a franchise that has made them $15 billion at the global box office.

Many studios have tried to cobble together their own cinematic universes in the years since the MCU kicked off. Some have been successful, with The Conjuring universe of interconnected horror movies perhaps the best example currently. Then there are tremendous failures like Universal's Dark Universe, which failed before it even really got going with The Mummy last year. Then there's the DCEU, which has had hits with Wonder Woman and major misses with Justice League. But nothing has come close to what Kevin Feige and Marvel Studios has accomplished. That all started with Iron Man a decade ago.