Living at the end of an era, what are the historical lessons can we learn from civilizations in collapse? We speak with David Carballo, Boston University archaeologist and anthropologist about the lost city of Teotihuacan which, at the start of the Common Era, was one of the largest cities in the world, boasting a population of more than 100,000 inhabitants from all corners of Mesoamerica. But all things end, and the capital city of the Teotihuacanos was no exception. Climate change, the collapse of social trust, and rising inequality meant that a few centuries later the builders of the city were buried by history. Studying what remains of the art and artifacts can shed some light on changes we can make in our own time stave off crisis.