Neil Oliver begins this stunning journey through the world's largest coral reef in the wake of James Cook, and in the hands of the Australian Navy's hydrography team. Brendan Moar discovers an Australian community overcoming wretched beginnings by renewing island family ties. Tim Flannery is granted rare access to a scientific research zone to examine coral history. Xanthe Mallett dives a spectacular wreck in search of answers about its calamitous sinking. On an idyllic island, Neil Oliver uncovers a bloody tale of cultural misunderstanding. Finally, at the southern end of the Great Barrier Reef, Emma Johnston heads underwater with Google to take the reef into homes around the world.

• Brendan Moar
• Xanthe Mallett
• Neil Oliver