Sir David Attenborough goes back in time to the roots of the tree of life, in search of the very first animals, telling their story with stunning photography, state of the art visual effects and the captivating charm of the world’s favorite naturalist.

Coral reefs are the nursery for all life in the oceans, a remarkable ecosystem that sustains us. Yet with carbon emissions warming the seas, a phenomenon called "coral bleaching" -- a sign of mass coral death -- has been accelerating around the world, and the public has no idea of the scale or implication of the catastrophe silently raging underwater.