We know a lot about early human societies, especially as they grew more complex and morphed into states, empires, and nations. But there’s a lot that we don’t know, such as why early humans began farming in different parts of the world around the same time, or why most early complex societies shared common characteristics. In this episode, historian David Christian and archaeologist Peter Bellwood discuss why humans migrated, farmed, and built more and more complex societies. Click here to learn more about Big History.