A mammoth Tsunami strikes the eastern seaboard. It would be a disaster of epic proportions. Some scientists believe this catastrophe could happen one day, but how? This episode shows the Atlantic island of La Palma has collapsed several times in mega-landslides. Another could trigger a tsunami with enough power to cross the Atlantic Ocean and decimate the US East Coast.

600 miles off the coast of South America in the Pacific Ocean there are 120 tropical islands that erupted from the deep ocean floor more than 10 million years ago. Journey from the lava ramparts to its fiery heart, we'll discover how the Galapagos archipelago became one of the most important areas of biodiversity in the world.
Those swept here by storms and currents survived million to one odds to find untouched islands free from competition. These hardy pioneers evolved in remarkable ways in what's known as Nature's Greatest Experiment. Home to bizarre specialists and unexpected giants, the most precious collection of island creatures on Earth.

Seafood is a substantial part of the daily diet of over three billion people and oceans absorbs almost a third of all the greenhouse gases we emits. Buy the ocean it is not what it once was. Scenes of extraordinary ocean abundance now only exist in far-off places or in tales from the past. We urgently need to mend our relationship with our oceans and allow them to thrive once again.
Prince William, David Attenborough and Shakira find out about inspiring people and projects across the world that can help us stop damaging the oceans and enable their revival.

In changing seas and oceans, cephalopods like the cuttlefish and the giant Pacific octopus must rely on their remarkable intelligence to survive. Their alien appearance comes with astonishing resources, independence, and invention. And there's still so much to learn about these rarely seen legends of the deep.

In the second episode, Will Smith descends 3,300 feet to the bottom of the ocean in a deep-water submersible, where even fewer people have gone than outer space. Along the way down, Will and explorer Diva Amon investigate how colour is used in the natural world and the role of bioluminescence. In the oceans, nearly 80 percent of animals use bioluminescence in some way, possibly the most common form of communication on the planet.

On the trail of tiger sharks in the Pacific, Will Smith explores the power of smell. Sharks have a sense of smell that's hundreds of times more potent and accurate than that of humans. An enormous part of their brain is dedicated to smelling, to finding their way through the vast expanse of the ocean.