How to build a cinematic universe: the secret to Marvel’s enormous success among a history of failures

Since Iron Man was released on the big screen in 2008, the Marvel Cinematic Universe (MCU) has grossed over US$30 billion, from movies to TV shows, to merchandise and comics. As commentators and the media have pointed out, central to its success is the employment of a very absorbing and complex “shared universe.”.
Several shared worlds have emerged following the MCU, such as Legendary Pictures’ MonsterVerse (including Godzilla and King Kong), James Wan’s Conjuring universe, the Star Wars universe, and the rebooted DC Universe.
You would be surprised to learn that they’ve existed for a very long time – but that most of them never quite get out of the blocks.
What is a shared universe?
It is difficult to give a firm definition of the concept of “shared universe” because it comes up so often with other closely-related ideas like spin-offs, franchises and crossovers.
In the most basic sense, you might view a shared universe as being some kind of world that contains a minimum of two texts (such as TV show, movies, video game or book) which are independent but share in elements of each other’s stories.
The stories can have other main characters, other plots, or even other worlds – but there will be, at the very least, some indication they occur within the same larger world.