So why don't we take a look at all three and see if we can figure out why the Columbian Exchange is going to be on the test. So we're going to start with diseases because without a doubt, I think this is going to have the most powerful impact on both worlds. And just so you know, before we tell the story, Old World wins. If we think about the peoples of the New World, these are people that came over the Bering Strait land bridge 10,000 years ago. And when they came over, they're not hauling tons of animals, and it's really cold. These are two factors that are going to really limit the amount of diseases that are coming into the New World. It was a healthy place to live.