World-ending or universe-threatening events happen so frequently in the DC universe you could probably set your watch by them. With such a wealth of catastrophes to look through, a question naturally emerges - that being which of these crises actually feels the most threatening.
Because while there are endless calamities that have threatened the world, not all of them were made equally. Some events have that extra something, be it a more imposing threat, or a more widespread one, that makes the whole thing feel so much more dangerous than your run-of-the-mill apocalyptic scenario.
These don't always have to just be about the potency of the threat, either, as complicated issues that can't just be fixed by punching something often appear all the more problematic.
No two cataclysisms are exactly alike in what makes them so dramatic, and that's exactly why these types of events can work again and again so well.
Between evil alternate worlds, threats to the entire multiverse, and even a tasteful sprinkling of zombies, DC have proved time and time again that if there's one thing they do right, it's having catastrophic Doomsday events.