10 Biggest Catastrophes In DC Comics
6. Zero Hour: Crisis In Time
For anyone who got a kick out of seeing Hal Jordan under the villainous Parallax alias, Zero Hour is a literal godsend, as the main threats within the events are him, and another ex-hero in the form of Hawk, who now goes by the villain moniker of Extent.
Both characters' plans involve messing with the DC timeline, in a series of events purposefully contrived to fix existing problems that DC had with their universe at the time, such as characters not ageing despite the timeline progressing, or some characters having their backstories retconned to fit more suitably into the overall franchise.
This all sounds quite tame, but in order to pull it off, more or less every hero or superhero group in existence had to be seriously threatened, with us seeing countless heroes maimed or killed before the series-wide reboot that came with the end of the event - suitably created by another Big Bang.