"Mr Stark, you've become part of a bigger universe. You just don't know it yet."
That's what Samuel L. Jackson's Nick Fury told Tony Stark in Iron Man's surprise post-credits scene, and every comic book fan on the planet felt their jaw drop when the S.H.I.E.L.D. Director mentioned the "Avengers Initiative."
At that time, there were tentative talks for Jon Favreau to helm The Avengers, while The Incredible Hulk scribe Zak Penn was writing the screenplay (which is why Tony tracked down General "Thunderbolt" Ross and mentioned putting a team together which was seemingly set to assemble to face the Jade Giant). However, by the time Iron Man 2 rolled around, Fury no longer wanted Iron Man on the team, and Marvel Studios went back to the drawing board and hired Joss Whedon to write and direct.
The news broke on April 13th, 2010, and fans were conflicted; his work on the Astonishing X-Men comic books had been well-received, while he had plenty of television experience thanks to shows like Buffy the Vampire Slayer and Firefly. However, his only movie credit was Serenity, and putting Earth's Mightiest Heroes in his hands felt like a major risk.
Despite that, when our first look at The Avengers arrived at the end of Captain America: The First Avenger, the response was overwhelmingly positive, and that would continue to be the case as more footage was revealed. By the time we got to watch the movie in theaters, it's fair to say we were all surprised by just how much content hadn't been shared in trailers. Moments like The Hulk battling Thor on the Helicarrier and those money shots of the team assembling played in front of totally fresh eyes - a rare treat which Marvel Studios has ensured is something they still do to this very day.
The Avengers earned a mighty $18.7 million during Thursday night previews, and went on to have a massive $200.3 million record-breaking opening weekend. Ultimately, the movie made $1.51 billion at the worldwide box office, a rare figure to hit at the time, and one which made Whedon's superhero ensemble the highest-grossing superhero film ever.
Since The Avengers was released, the genre has continued to grow, while the Marvel Cinematic Universe entered a new era that upped the humour, increased the surprises, and embraced a shared world which would ultimately culminate with Avengers: Endgame, the biggest movie in history.
This first team-up was a game-changer for films in general, and proved that the concept of a shared world could work across multiple franchises (even if those that tried to imitate it have often failed). Compared to some of the movies which followed it (including Whedon's sequel, Avengers: Age of Ultron ), The Avengers may seem relatively small in scale, but it's an historic piece of cinema which deserves to be remembered as a classic...even if it didn't feature that "Avengers Assemble!" battle cry.