In the last episode of Brian's epic journey across the Universe, he travels from the fossils of the Burgess Shale to the desert sands of the oldest desert in the world. His goal is to show how light holds the key to our understanding of the Universe, including our own origins.

Originally released by BBC, 2011. Streaming video file encoded with permission for digital streaming by Infobase on April 30, 2015.

In the Beginning (10:29); --Light (8:08); -- Speed of Light (9:20); -- Color of Light (8:55); -- Big Bang (8:45); -- Milky Way (6:16);.