And in Crimea you still had some Italian tradesmen and they were holed up in a city called Kaffa. And basically what occurred was as the Mongols were affected with the plague, with bubonic plague, and they couldn't do the siege anymore, they started tossing the dead bodies over the wall. It's probably the first instance of biological warfare in human history. But then these Italian tradesmen, these sailors, they got infected and at the same time they're trying to get the heck out of Dodge. So they jump on the boats, they go on the Black Sea and they start heading towards Europe. And along the way they're going to stop at different ports, they're going to be turned away. And when they stop, if those rats get off that ship, it's going to start infecting human beings.