Series host and narrator, Alan Alda, confronts the puzzle of why our ancestors in Africa got the Spark and evolved into us, while the first humans to leave Africa for Europe–the Neanderthals–never did. Why did we flourish, while they changed very little for thousands of generations before eventually dying out?

Alan Alda joins researchers studying human children and chimpanzees to discover why we share some skills with our closest living relatives, but have far surpassed them in our most uniquely human capabilities. Though we both descend from a common ancestor and are genetically so similar, why are we worlds apart in our behaviors and abilities?

Peer into Alan Alda’s head to find out which parts of our brain are responsible for our most human characteristics. Where do tool use and language reside? And how do our brains allow us to understand symbolism, figure out what others are thinking, and even travel in time? Are insight and imagination what really make humans unique?