What is our Future? (S01E05)

Brian wraps up his journey into humanity's role in the cosmos by pondering the next chapter for the ape that ventured into space. He travels to Northern Spain to investigate a cave that once sheltered our distant ancestors. His adventure continues in the Arctic, where he seeks to uncover what distinguishes us from other species. Finally, Brian ascends to the frigid heights of Svalbard, where he discovers the key to ensuring our survival for the long haul.