Nukes. If you grew up in the 50s, 60s, 70s or 80s the specter of nuclear annihilation was always just around the corner.

Throw in the occasional bio-weapon scare, internet worm, Y2K, etc. there has always been something dangling over our heads that’s going to end it all.

But mostly nukes. Full-scale nuclear exchange would have been not much of a surprise had it happened.

Y2K, Climate Change (global cooling, global warming), ozone layer, Russians, Muslims, to name a few. Now go ahead and tell me why these don't count.