Part 2: Visitors David discovers the creatures that visit the reef every year, from birds to whales, some travelling thousands of kilometres to get there. Using the latest technology, David dives into the shark-infested waters of Osprey Reef in the Triton submersible. Sixty years after his first visit to Raine Island, he returns to the nesting grounds of the green sea turtle and at Lady Elliot Island marvels at manta ray cleaning stations. New tracking technology allows David to follow the story of visitors like the dwarf minke whales. Stunning satellite imagery and computer animation reveal their journey and David discovers their surprising reasons for returning and why the reef is vital for their survival.
Professor Brian Cox follows Earth's epic journey through space. He takes to the air in a top-secret fighter jet to race the spin of the planet and reverse the passage of the day. In Brazil, a monstrous wave that surges up the Amazon River provides an epic ride of a different kind - chased by a top surfer through the rainforest, this tidal wave marks Earth's constant dance with the Moon. Greenland experiences some of the biggest swings in seasons in the world, but despite the deep freeze, the harsh winter brings opportunity to the Inuit people who live there. All this spectacle here on Earth signals that we are thundering through the universe at breakneck speed. Brian explains why we can't feel it and how understanding motion brings us to understanding the nature of space and time itself, leading to the astonishing conclusion that the past, present and future all exist right now.
Mammals' ability to learn new tricks is the key to survival in the knife-edge world of hunters and hunted. In a TV first, a killer whale off the Falklands does something unique: it sneaks into a pool where elephant seal pups learn to swim and snatches them, saving itself the trouble of hunting in the open sea. Slow-motion cameras reveal the star-nosed mole's newly-discovered technique for smelling prey underwater: it exhales then inhales a bubble of air ten times per second. Young ibex soon learn the only way to escape a fox - run up an almost vertical cliff face - and young stoats fight mock battles, learning the skills that make them one of the world's most efficient predators.