The Human Spark | Clip | If It Ain't Broke...
Archaeologist John Shea explains the context and construction of one of early humans' first tools-the stone hand ax.
Archaeologist John Shea explains the context and construction of one of early humans' first tools-the stone hand ax.
Alan Alda visits dozens of scientists on three continents -- and even undergoes an examination of his own brain -- to find the answer to one question: What makes us human?