Answer: Iron Man

Over the years, there have been many comic-based films, but in the late 2000s, Marvel took things to a new (and wildly profitable) level with the creation of the Marvel Cinematic Universe. Rather than simply release a movie here or there about a particular character (perhaps spinning it into a trilogy like was done with the Spider-Man series), Marvel instead focused on creating a continuous body of work (including TV shows and companion comics) that echoed the original Marvel Universe they had created for their comics.

The project started with “Phase One”, a period of film releases intended to introduce the characters and assemble them into The Avengers. The leading film was 2008’s Iron Man, followed by The Incredible Hulk (only a month later in 2008), Iron Man 2 (2010), Thor (2011), Captain America: The First Avenger (2011), and culminating in Marvel’s The Avengers (2012).

Building on the success of the original film and the subsequent phase, Marvel continued into Phase Two with six additional films—most notably, the incredibly successful Guardians of the Galaxy in 2014. Phase Three concluded with Spider-Man: Far From Home in 2019 and we saw the start of Phase Four with Black Widow in 2021.

While some critics have complained that some of the individual movies have suffered due to service to the franchise and cross-movie continuity, the series as a whole has been a blockbuster success, collectively earning over 25 billion dollars at the box office.