In which John Green returns to teaching World History! This week, we'll be talking about the idea of civilization, some of the traditional hallmarks of so-called civilization, and why some people would choose to live outside the civilization model. It turns out that not everyone who lives outside of what we traditionally think of as a "civilized" social order is necessarily a barbarian! To defuse any tension you may be feeling, I'll just tell you now that the Mongols are back.