Over 60,000 years ago, the first modern humans—people physically identical to us today—left their African homeland and entered Europe, then a bleak and inhospitable continent in the grip of the Ice Age. But when they arrived, they were not alone: the Neanderthals had already been living there for hundreds of thousands of years. So what happened when the first modern humans encountered the Neanderthals? Did we make love or war?

That question has tantalized generations of scholars and seized the popular imagination. In 2010, a team led by geneticist Svante Paabo announced stunning news. Not only had they reconstructed much of the Neanderthal genome—an extraordinary technical feat—but their analysis showed that “we” modern humans had interbred with Neanderthals. In Decoding Neanderthals, NOVA explores the implications of this exciting discovery. Were Neanderthals really mentally inferior to us—as inexpressive and clumsy as the caveman they inspired? Or have we seriously underestimated our mysterious, long-vanished human cousins?