So how did the Black Death start, the great plague, the great mortality? We do know that there were some type of natural disasters that occurred in the 1330s in the Central Asia Mongolia area. It could have been an earthquake, but there was drought, there was famine, there was a change in the environment. That probably caused some of those varmints, some of those rodents, some of those rats to go scurrying about. And at the same time period you have the Silk Road, which is this transport system between China and Europe. And now it's not as easy as just saying that the rats got on the Silk Road and they were carried into Europe. That's not how it happened.