In which John Green teaches you about World War II, aka The Great Patriotic War, aka The Big One. So how did this war happen? And what does it mean? We've all learned the facts about World War II many times over, thanks to repeated classroom coverage, the History channel, and your grandfather (or maybe great-grandfather) showing you that Nazi bayonet he used to keep in his sock drawer and telling you a bunch of age-inappropriate stories about his harrowing war experiences. So, why did the Axis powers think forceful expansion was a good idea? (they were hungry). So why did this thing shake out in favor of the Allies? Hint: it has to do with the fact that it was a world war. Germany and Japan made some pretty serious strategic errors, such as invading Russia and attacking the United States, and those errors meant that pretty much the whole world was against them. So, find out how this worldwide alliance came together to stop the Axis expansion. All this, plus Canada finally gets the respectful treatment it deserves. Oh, and a warning: there are a few graphic images in this episode. Sensitive viewers may want to use caution, especially around the 9:15 mark.