Quantum physics starts with the 20th century as scientists try to understand light bulbs. This simple quest led scientists on a deep journey.

Professor Jim Al-Khalili reveals how Einstein thought he'd found a fatal flaw in quantum physics that implies that subatomic particles can communicate faster than light. The host of "The Amazing World of Gravity" and "Everything and Nothing" shows how robins navigate using quantum entanglement, how our sense of smell is touched by quantum vibrations, and how physics might play a role in evolution.