As a kid I was fascinated by the fact that back in the day there used to be woolly mammoths, sabertooth tigers, milodons, etc. roaming across the plains. I mean, what sort of six year old boy couldn't love something like this:
For the uninitiated, that's a sabertooth tiger a.k.a. a Smilodon taking down a sloth while a woolly mammoth looks on.
I'd always wondered what happened to all these animals. I'd read that the Younger Dryas ice age came along and killed most of them off and the remaining few were killed off by early man.
But now there's a new theory! Apparently not only was there an ice age, but then a comet came and slammed into Earth at the same time (talk about bad luck; glad I wasn't around then). The good news was that diamonds rained from the sky. The bad news was that the impact of the comet set everything on fire, even the air and definitely anybody within a couple of thousand kilometers of the impact site. Oh yeah, and there were likely floods caused by the sudden melting of glaciers.