End of the world
What's funny is that one of the times when we truly were knocking on Armageddon's door, not a soul was predicting it.
I'm talking about that Soviet radar operator who saved the world by going against orders multiple times and not ordering a counter strike against the US when his equipment gave compelling evidence of a massive incoming American missile strike.
We were never closer and never more clueless. My guess is, if the end does come in our lifetimes, it'll be in that form - sudden and without warning signs.
Art