And there's a history lesson in that, Pants, which is that when people have to choose between civilization and warm genitals, they choose warm genitals. Best wishes, John Green. And now a note from our sponsor. Today's episode of Crash Course is brought to you by the all-new Oldsmobile Byzantium, mixing power and luxury in a way that's never really... Oldsmobile isn't a company anymore? And Byzantium is a place? Are you sure? So remember when I said the Roman Empire survived till the 15th century?