And just to get a sense of the scale of this, if we were to go 2,000 years ago to the time of the Roman Empire, that would be roughly here on the timeline. If I were to say, when were the pyramids built, that would be roughly there on the timeline. So by human standards, this is a very long period of time. And I didn't choose this time span arbitrarily. 200,000 years is about how long we believe anatomically modern humans have been on our planet, our subspecies of Homo sapiens sapiens. Now the reason why I show these stone tools is because the ages, the periods of modern humanity, or even pre-modern humanity, are named after the types of tools that have been found in archeological digs. So most of even pre-human, or near pre-human, and human history has been the Paleolithic period, or Old Stone Age.