In this three-part series, host Alan Alda searches for the originand nature of uniquely human abilities - the "human spark."

Uniquely human abilities - to think in symbols; recombine thosesymbols into infinite meanings; invent a technology to disseminatethe message; ponder the past; speculate about the future; imaginethe unknown; build cities; compose music - constitute the "humanspark." In this three-part series, host Alan Alda searches for theorigin and nature of this spark.