In 2008, the first film in the Marvel Cinematic Universe, Iron Man, was released. Its announcement was received with what might politely be called muted expectation. And it is not hard to see why. It had been in production hell since 1990 with various studios trying to get it off the ground. The film had been turned down by 30 screenwriters. Even while shooting, actors were improvising dialogue off the cuff.

Iron Man made $585m. It was a film about an arms dealer turned good, wearing an iron suit to fight terrorists. Not the easiest sell perhaps. But it was perfect for the post-9/11 cultural milieu, and director Mr Jon Favreau shot it with a naturalism that was unheard of in comic-book films at the time. “You’d think you were watching a military thriller,” wrote Mr David Edelstein in his review for New York Magazine. It was the start of the unstoppable juggernaut.

Due to the wild success of Iron Man, Marvel was bought by Disney for an eye-watering $4bn. This was just 13 years after it filed for bankruptcy. But how can we explain this colossal change of fortune? What made the famously astute Disney part with so much cash? Well, they had an eye on the long game.

In fact, Iron Man spawned the Marvel Cinematic Universe as we know it, soon to be 22 films of unprecedented cinematic scope that have cumulatively raked in $15bn in box office receipts over 11 years. The MCU has employed the biggest actors of our generation: Mr Robert Downey Jr as Iron Man; Mr Chris Evans as Captain America and Mr Mark Ruffalo as the Hulk. Mr Samuel L Jackson played Nick Fury, a character whose role was to unite these disparate heroes over the course of their solo adventures. By 2012 the first phase of Marvel’s storytelling was complete: an ensemble film that had been unheard of in cinema, The Avengers, broke the worldwide box office, making $1.5bn.

“The mind boggles,” says Mr Germain Lussier, entertainment reporter for io9 and Gizmodo. “It never should have worked.” In 1996, Marvel had filed for bankruptcy and sold off vast swathes of its best-known characters, such as Wolverine, Spider-Man and the X-Men. Fox, Sony and other studios snapped them up. Other film companies made movies with their Marvel characters. But Marvel still wanted a throw of the dice. Iron Man was the first of its gambles – a little-known comic book character, far less culturally significant, and less well-known than the likes of the X-Men and Spider-Man.

Marvel, and Disney, have changed cinema, and Hollywood forever, significantly because it has focused on storytelling and on the franchise above individual actors. In Marvel films, each character plays a lead in their own movie, but an ensemble part in the greater whole. As well as being an interconnected part of a much bigger titan, each Marvel film is also its own entity. They have their own voice, often taking inspiration from wildly different genres. Thor: Ragnarok (2017) is often considered almost a buddy road trip movie. Captain America: The Winter Soldier (2014) was a thriller and a commentary on mass surveillance.

These solo films have also changed the director-studio paradigm. Marvel has plucked its directors out of indie filmmaking and catapulted their careers into the very cosmic world their films transport us to. A tenet of Marvel president Mr Kevin Feige is “hire indie talent, as much as possible”. Mr Ryan Coogler’s debut feature Fruitvale Station was a big Sundance hit, and soon enough he was brought on to direct 2018’s Black Panther. Even more out of the box for Marvel was New Zealand’s Mr Taika Waititi, who directed the blockbuster hit Thor: Ragnarok and transformed fans’ perceptions of the character.

“Even in our longest-running film franchises, like say James Bond or Friday The 13th, the narrative connections are tenuous at best,” says Mr Lussier. “But Marvel, from day one, has crafted one story that’s now at 20-plus movies and counting. It’s astounding and unprecedented. Like watching a television series where every episode costs a hundred million dollars with the biggest stars and talent in the world. Plus, they’ve done it with such incredible critical and financial success.”

But it goes beyond just money; superheroes are now as much a part of our cultural zeitgeist as James Bond is to the English. Little girls and boys dress up as Captain Marvel and Captain America. Films such as Black Panther have rewritten the pre-conceived rules of Hollywood casting; that a film with an African-American cast could ring up $1.34 billion at the box office was at one point unimaginable in Hollywood. Today it is happily a reality that is, in part, down to Marvel.

As Mr Lussier says, Marvel has “forced other studios to try to play catch up”. DC made a pig’s ear of its cinematic output with often jolting narratives that weren’t carefully crafted from the get-go. Its movies, such as Man Of Steel, Batman V Superman: Dawn of Justice and Wonder Woman have often yo-yo’d in mood and tone, and seem to be almost planned off the cuff. Even Universal Studios attempted to create a so-called “dark universe” with its monsters, such as The Mummy, which fell flat upon its release in 2017. “Most have realised they can’t duplicate the formula,” says Mr Lussier.

Another part of Marvel’s appeal is its use of post-credit stingers. “End-credit scenes have been a thing since Ferris Bueller’s Day Off,” says Mr Lussier, of the famous post-credit scenes, where characters in the inter-connected universe arrive in each other’s films to plant seeds for future releases. “Marvel didn’t create them, but they made them fashionable and essential.” Those character seeds are the bedrock for the universe. “Great movies often reward fans who watch all the movies before and after them. Marvel’s films give fans an added sense of accomplishment and excitement [that other studios don’t].”

Now, 11 years of cinematic storytelling and 21 films leads us to the release of Avengers: Endgame this month, a culmination of Marvel’s steadfast approach to the narrative. The heroes faced obliteration in last year’s Avengers: Infinity War. Now we wait to see what happens next. Mr Feige has said that it is the end of all those years of storytelling. It’s a finale worth waiting for and it’s also the start of something new, of what comes next in Marvel’s forthcoming phase of films. All this time and we still don’t know where things are headed. Marvel, and Disney, still keep us guessing.