New York City

We have a few outliers here and there—a jaunt to Germany, some scenes over the ocean and the farthest reaches of outer space—but most of the key action takes place in the city that never sleeps.

New York City plays a huge role in Marvel Comics, and that's where the main importance of the setting comes from. (Otherwise, we'd just be talking about "Planet Earth," since that's the little blue planet that the aliens are hellbent on invading.)

Back in the day, when comic books were still being established as your go-to-place for square-jawed do-gooders in four-color outfits, New York was the hub of it all. Many of the key writers and artists who helped bring the industry to life—guys like Jack Kirby, Bob Kane and Stan Lee—grew up in New York, the children of Jewish immigrants who found new homes on Manhattan Island. (Jerry Siegel and Joe Schuster, who created Superman, hailed from Cleveland, but the company they sold their character to was based in New York.)

So all those guys were working out of Manhattan office buildings, and used the city around them as inspiration. You'll notice that a lot of comic book fights take place in big cities, among the skyscrapers and the trolley cars and hapless citizens screaming for cover.

You can easily look at comic book characters as mythic figures: the heir apparents to Perseus, Hercules, and the Knights of the Round Table. Myths only work if they connect to the people they're intended for, and while most of us love the idea of an ancient Greek warrior cutting the head off a snake-haired monster, or an English knight wearing two hundred pounds of pig iron and mixing it up with a fire-breathing dragon, we're not connected to either those times or those places in our daily lives.

The big city, though, is something all of us know and love. Even if we live in a small town, the city is the place where our country found its identity. It's where business thrives, where people came together to build something great, and where—according to popular conception anyway—anyone can arrive and find a place to grow and succeed.

As our biggest city, New York becomes a great stand-in for all the others: the place where we can celebrate America and the things we stand for, twenty-four hours a day, seven days a week. Our mythology finds a natural home there, and you're not going to see comic books stray too far from the naked city anytime soon.

Why Pretend?

Now here's where it gets funky. For the longest time, the 600-pound gorillas on the comic book scene belonged to what we now know as DC Comics: Superman and Batman particularly, but also characters like Wonder Woman and the Flash.

Most of them were based in big cities as befits the model… but none of them were real cities. Superman had Metropolis. Batman was in Gotham. The Flash worked out of Central City, and Wonder Woman has a whole made-up island to come from (though admittedly, she does show up in real-world cities like Washington).

Why? Well, it's a lot easier to come up with parks, bridges and other places that serve your story without having to hunt down a real site and hope that it fits what you need. And with DC's superheroes ruling the comic book roost for decades, nobody saw any reason to change.

And then came Marvel. They were Johnny-come-latelies to the comics scene, arising in the 60s, almost thirty years after Superman kicked the whole superhero thing off. They were the first real challenge to DC's status as king of the cage, and they definitely wanted to set themselves apart from their aging competitors.

There was an easy way to do that.

With the artists, writers and creative movers and shakers literally living in New York, they could set their stories just down the block from wherever they worked. There aren't made-up locations, and there's no fictional city map that you have to keep track of. Just draw a picture of the Chrysler Building, plop a cackling supervillain on top of it, and you're good to go.

New York thus became something of an unofficial capital of the Marvel Universe. Heroes like Captain America and Spider-Man were born and raised there (Cap in Brooklyn, Spidey in Queens), while big-time superhero teams like the Avengers and the Fantastic Four set up their secret headquarters there. (Professor Xavier's school, home to the X-Men, lies just upstate in the county of Westchester.)

New York was in Marvel's DNA, and they saw no reason at all to be quiet about it.

"That's great," we hear you say. "But the Marvel Cinematic Universe doesn't spend much time there." And yeah, that's true. Movies need a certain visual distinction to set themselves apart from the others, and since these movies are introducing these characters to a big chunk of the audience for the first time, they wanted settings that reflected their personalities.

Iron Man, the celebrity narcissist, keeps his crib in Los Angeles, for example, while Thor's first two movies are set in rural New Mexico (where you can see the stars stretching all the way to Asgard) and London (a very old city that can remember when Thor-worshipping was an actual thing).

But none of those movies were The Avengers, which served as the flagship to the whole thing and which the filmmakers were hoping (correctly as it turns out) was going to be the biggest thing since sliced bread. That meant they couldn't set it in L.A. or St. Louis or even Paris and have it work.

No, it all needed to happen in the Big Apple: the place where comics were born. (Source)