Under The Sea: The Great Barrier Reef

Iolo Williams explores Australia's Great Barrier Reef, one of the world's richest marine environments, in a bid to understand if the reef and the myriad of life it supports will survive for future generations.

Iolo Williams looks at the devastating effects of coral bleaching and tropical cyclones, but also uncovers incredible signs of regeneration and an abundance of marine life which continue to thrive despite the threats, giving hope for its survival.

Adventurer Iolo Williams goes diving on the Great Barrier Reef to find out how healthy it is.