Coral Seas (S01E06)

Amazingly beautiful and complex, coral reefs develop from humble beginnings. Tiny larvae settle and then over hundreds of years the intricate and fragile reefs that we so enjoy grow, inch by inch. Reefs are adorned with spectacularly colourful life, but it is no tropical paradise. Space is at a premium and even the coral itself fights to survive. And then, at night, the sharks come out to hunt. Layer upon layer the coral supports innumerable animals, but one big storm can threaten the entire community. (BBC)