This brief piece from NPR is about an extinct civilization in present-day Phoenix AZ. It was a farming civilization that died out because of overpopulation combined with climate change. The remnants have been largely covered up by the modern city, much like past civilizations are so often built on top of one another. It raises some interesting questions about preservation, why humans prefer certain locations for settlement, and the more existential question of how many societies have come and gone without our having ever known about them.