They were in the game long before Marvel and DC ... and they never needed a cheesy cover of "Come Together," either.
Sure, you know all about the Avengers and the Justice League, but the idea (and practice) of a "shared movie universe" actually came into being over 70 years ago with the emergence of the Universal Monsters. Dracula and Frankenstein (both released in 1933) got things going, and from there we got The Mummy (1932), The Invisible Man (1933) and the first Universal monster movie sequel, Bride of Frankenstein (1935).
The Wolf Man (1941) was late to the party, but after that we got the first crossover team-up with Frankenstein Meets the Wolf Man (1943), a film that originated as a joke over lunch and went on to, well, make a lot of money.
And there's more ... much more. Watch below.