8. Crisis on Infinite Earths (Marv Wolfman)
You could argue that Crisis on Infinite Earth's was a simple exercise in tidying up DC's extremely messy, 50-year-old continuity and that it most certainly was (Batman for example was shown to be young, vital and active well into the 80's, while also being a decorated World War II hero - something just doesn't add up there does it). So in essence, with Crisis on Infinite Earths, DC's Multiverse was officially born and argued that whenever one story didn't quite reconcile with another, that meant they were each set in different Universes. Essentially, in Infinite Crisis, the DC heroes work to halt the inter-dimensional ploy of the Anti-Monitor, a giant, God-like being who plans to destroy all of the known Universes. At the culmination of what was one of DC's first proper crossover events, the Anti-Monitor is stopped and the main-canon DC heroes are returned to their original Universe with no memory of the existence of a multiverse, thus effectively explaining away any holes in DC's continuity. Since then, DC writers have used this multi-verse to essentially tell any story they want, whether adhering to continuity of not. Complicated I know, but when you think about it, it was a pretty smart move on behalf of DC's creative heads at the time. If Warner Bros. want to provide a Justice League movie that's more along the lines of The Avengers - more action-oriented, that is to say - than that's fine, there're plenty of JLA stories that deliver just that. However, should they desire something entirely more unique and indeed with much at stake than just
one Earth, Crisis on Infinite Earths, for me, is clearly the way forward.