The Neanderthals and modern humans must have co-existed in Europe for several thousand years. What happened when they encountered each other and how they influenced one another are riveting questions. Jean-Jacques Hublin and his team at the Max Planck Institute for Evolutionary Anthropology in Leipzig are searching for answers to them. In the process, they have found clues as to what the Neanderthals learned from Homo sapiens—and what they didn’t.