On the other side of the world under the crystal clear blue waters of the Pacific Ocean lies one of the most enchanting places on the planet. Over ten thousand miles away on the north eastern coast of Australia lies the Great Barrier Reef, one of the natural wonders of our world. It provides shelter to some hidden wildlife sanctuaries that contain some magical marine creatures. Invited on a reef adventure by Emmy Award-winning underwater cinematographer and marine biologist Richard Fitzpatrick, conservationist and naturalist Iolo Williams dives deep beneath the surface of the coral sea to discover what state this natural wonder is in. Together they travel from the extreme swells of the northern part of the reef right down to the cooler pristine corals of the south. They discover how healthy the Great Barrier Reef really is in some of its key locations to see and find out if there are real signs of hope the reef can survive the threat of global warming.

• Documentary