To say 'Avengers Assemble' is currently enjoying success would be an incredible understatement. It exceeded all expectations by taking the biggest ever opening weekend in the US — a whopping $207 million (£128 million) - and did it by beating the previous holder of that title, 'Harry Potter and the Deathly Hallows: Part 2' by almost $40 million.
Its current worldwide takings mean it's on target to break the $1 billion mark.
[Related story: Avengers take global box office by storm]
[Related story: Samuel L. Jackson vents fury over bad Avengers review]
[Related feature: Everything you need to know about Avengers Assemble]
But why is 'Avengers Assemble' about to become one of the most successful films ever? We investigated...
First Marvel's newly founded film wing introduced 'Iron Man' to the world, with a wise-cracking Robert Downey Jr. as its lead back in 2008. A scene following the film's credits teased an eventual 'Avengers' film, but plans weren't set in stone until the film proved a runaway success.
The other superheroes in the team, Hulk, Captain America and Thor, each had their own movies as well, which set up each of the lead characters and familiarised the audience with the concepts of the Marvel universe and smaller characters like Black Widow.
It's a film that in effect had four years of heavy marketing.
In Whedon we trust... Joss Whedon, director of 'Avengers Assemble' (Credit: Marvel Studios)
With 'Avengers Assemble', Marvel took a gamble by entrusting their flagship property to a director with only one big screen credit.
While critically lauded, geek god Joss Whedon's debut 'Serenity' was still a flop. However his work on cult TV shows 'Buffy the Vampire Slayer' and 'Firefly' proved that he was adept at writing and directing ensemble pieces. He also had experience with Marvel, having written a string of X-Men comics in 2004.
Whedon proved to be the perfect man for the job, skilfully dividing up screen-time between the heroes, the supporting characters and the villain, without ever detracting from the overall story. And he did it all with a keen sense of humour, making the film funnier than most mainstream comedies.
His hiring followed the Marvel pattern of leftfield directors: 'Elf' helmer John Favreau took care of 'Iron Man' and its sequel while Kenneth Branagh 'Thor'. All three ended up doing fine jobs.
Earth's Mightest Heroes... Mark Ruffalo and Robert Downey Jr. (Credit: Marvel Studios)
A great cast
Before Robert Downey Jr. became 'Iron Man' in 2008, he was best known (to many) for stints in rehab and a part in 'Ally McBeal'.
The film made him a massive movie star, and set the blueprint for Marvel thinking outside the box when it came to their leading men and women.
Chris Evans and Chris Hemsworth both nailed their parts as the American golden boy Steve Rogers and Norse god Thor, neither of which were what were expected. Then there's Tom Hiddlestone and Mark Ruffalo, two indie darlings who undoubtedly steal the show in 'Avengers Assemble' as Loki and The Hulk respectively.
In fact, the most recognisable stars involved weren't even super-powered, Samuel L. Jackson and Scarlett Johansson.
Critics of Marvel will say the infamously tight studio casts this way because they don't like to pay top-tier wages, but the strategy has paid off so far.
Feeling green... Obvious captions make Hulk mad! (Credit: Marvel Studios)
Ask anyone what their favourite moment from 'Avengers Assemble' is, and the chances are they will mention something involving The Hulk.
Despite two films that failed to do him justice, and with a third actor now taking on the role, everyone still loves the big green monster.
What helped this time around is that Whedon moved away from the angst-ridden, tortured versions of the character played by Eric Bana and Ed Norton. He retained the hint of tragedy that the character needs but made him entertaining and FUNNY as well.
Speaking of which...
As the years went by 'Harry Potter' got bleaker while 'Spider-Man' went from light romp to emo-inspired rubbish. Only Christopher Nolan's Batman trilogy got away with it because it was dark in the first place (and really really good).
The Avengers have bucked this trend. Across the five build-up films and 'Avengers' promotion, the sense of fun has never diminished. They remain bright, colourful films that are entirely self-aware and proud of their comic book heritage.
Inherently ridiculous and damn proud, the Avengers chime into a deep-set feeling of nostalgia that everyone has. A nostalgia for movie stars that quipped more than they frowned and for larger than life characters who fight for good and do it with a nod and wink.
The Los Angeles Times called 'Avengers Assemble' "smartly thought out and executed with verve and precision", while the Hollywood Reporter said it was "engineered to charm the geek core and non-fans alike".
And that's the point. Films based on comic books have an inbuilt core audience that will usually watch them no matter what. But for a superhero franchise to appeal outside the fanboy set — and make loads of money - they need positive word of mouth. Which typically means good reviews.
It's no coincidence that the two most successful superhero films ever are also the most critically lavished. Right now 2008's 'The Dark Knight' has a 94% rating on Rotten Tomatoes, and 'Avengers' has 93%.
There's a good reason critically reviled flicks like 'Jonah Hex' and 'Daredevil' failed to set the box office alight.