Avengers Endgame The Marvel Cinematic Universe explained
What is the Marvel Cinematic Universe?
The Marvel Cinematic Universe - or MCU for short - is the shared place where all 22 films featuring the comic book characters are set.
Each tells its own distinct story but also connects with other films in the MCU, to tell an overarching tale. It's a technique Marvel Comics pioneer Stan Lee also used in his comics.
The MCU is the most successful film franchise of all time, making more than $18.2bn to date.
Why did Marvel start with these characters?
Marvel still owned the superheroes who form the core Avengers team - Iron Man, the Hulk, Thor and Captain America - so used the early MCU films to introduce these heroes.
Marvel then brought these characters together for the crossover film Avengers Assemble.
The first MCU film released, Iron Man, included a post-credits scene in which Samuel L Jackson's super spy Nick Fury gives the first mention of the Avengers.
What order should I watch the films in?
We suggest you watch the films in chronological order, rather than the order in which the films were released.
I don't have time to watch all the films! What can I skip?
Endgame is the finale of a series of 22 films.
But, don't worry, you don't need to watch every single one to be fully prepared.
Here are the 10 films you could skip and still understand the basics of Endgame.
The Incredible Hulk - you'll learn all you need to know about the key characters here in Avengers Assemble
Thor - ditto
Thor: The Dark World - you don't need to see this to get the gist of Avengers: Age of Ultron
Iron Man 2 - Scarlett Johansson fans may not want to skip this one, as it marks her entry into the MCU
ron Man 3 - Robert Downey Jr is always watchable, but skipping this won't leave you confused
Ant-Man - Scott Lang and his superpowers get introduced all over again in Captain America: Civil War
Doctor Strange - all you really need to know is this film introduces the Time Stone.
Guardians of the Galaxy, Volume 2 - there's some nice character development here, but it won't give you new information on the final battle
Black Panther - we hesitate to suggest you skip this Oscar-winning film, as it's one of the MCU's best, but other than introducing Wakanda as a location, you'll get most of the relevant information about the characters introduced here in Captain America: Civil War and Avengers: Infinity War
Captain Marvel - again, watch this if you can but if you're pushed for time, all you really need to know is that Carol Danvers (Brie Larson) got her powers from the Space Stone and she's going to be important to the final battle in Endgame. Also, the man who put together the Avengers - Nick Fury - lost his eye to an alien disguised as a cat.
What's so important about Avengers: Endgame?
Marvel's plans for its films are structured in phases, with each one ending with an Avengers crossover movie.
Avengers Assemble spelt the end of Phase One, and Age of Ultron brought Phase Two to a close.
Endgame not only ends Phase 3 but also wraps up the series of 22 films that Marvel Studios president Kevin Feige is now calling The Infinity Saga.
The new title for the first three phases of the MCU references their overarching story, which sees the gathering of the Infinity Stones (six powerful gems that grant their owner great power) and the war against the mad Titan Thanos (Josh Brolin).
Endgame will see the remaining Avengers try and rescue everyone, after villain Thanos got hold of all the Infinity Stones and wiped out half of all living things with a snap of his fingers in last year's Avengers: Infinity War.
All bets are off as to who makes it to the finish line in Endgame, as it also coincides with the end of the contracts of some of the biggest Marvel stars.
It's been widely reported that Chris Evans (Steve Rogers/Captain America), Chris Hemsworth (Thor) and Robert Downey Jr (Tony Stark/Iron Man) have come to the end of their contracts.
There's also been speculation that their Marvel co-stars Scarlett Johansson (Natasha Romonova/Black Widow), Jeremy Renner (Clint Barton/Hawkeye) and Mark Ruffalo (Bruce Banner/Hulk) have also reached the end of their tenure at the studio.
Though a solo Black Widow film is reported to be in the works, it could be a prequel, so there is no guarantee Johansson's character survives.
One thing is for sure though - whatever happens, it will take time for Endgame's story to unfold.
It's the longest entry in the MCU so far, clocking in at three hours and two minutes. That's the same length as the first instalment in Peter Jackson's Hobbit trilogy, An Unexpected Journey (2012).
What's the future of the MCU?
We can expect a major shake-up of the MCU, in the wake of Endgame.
Phase Four begins with the release of Spider-Man: Far from Home on July 5 2019.
According to producer Amy Pascal, the film "will start a few minutes after Avengers 4 wraps as a story".
Tom Holland's Spidey was one of many heroes wiped out in Thanos's Snap in Infinity War, but given his starring role in this film, we can expect he'll be alive and well before the Endgame credits roll.
New films involving other supposedly dead characters have also been confirmed for Phase Four.
Marvel Studios president Kevin Feige has confirmed Benedict Cumberbatch's Doctor Strange will return for a sequel at "some point in the future".
Chadwick Boseman is also likely to recover from his disintegration in time for Black Panther 2.
We also know a third Guardians of the Galaxy film has been confirmed, but we don't know which Guardians will return for it. At the end of Infinity War, Bradley Cooper's Rocket and Karen Gillan's Nebula were the only survivors from that franchise.
Feige has also hinted that Phase Four could include a solo sequel for Brie Larson's Captain Marvel.
Also in development are new films involving super-powered beings called the Eternals, and martial artist superhero Shang-Chi.