In the third episode, Will Smith crosses the Serengeti to catch one of the greatest events of nature. "An image, one and a half million wildebeests on the plains of Africa in the most dramatic migration on Earth, has stayed with me since around thirty years ago I picked up a National Geographic Magazine and saw it. And finally, I'm here to see it."

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.

Will Smith discovers hidden worlds of fast and slow in the Earth's oldest desert. Worlds where things go so fast or so slow we don't even know they're happening. This hidden world of speed is everywhere, even 80 feet underwater. Hundreds of tiny anemones, anchored to the rocks, but film them patiently, then speed it up, and this miniature world comes to life. A lizard's tongue is one of the fastest movements in the entire animal kingdom. An orca creates a shock wave by slapping her tail and that pulse can travel through the water at more than a thousand miles an hour. to stuns the herrings she hunts.

Will Smith confronts his fear of nature on powerful white-water rapids in Iceland. "Over five expeditions, I've followed explorers into situations that were straight-up scary. It was worth it to discover the Earth's wonders. But your boy was tripping more than once. Because when I see wilderness, you know, nothing but nature, I get nervous because I don't understand it."

This revealing film examines how human activity is setting off dangerous warming loops that are pushing the climate to a point of no return - and what we need to do to stop them. With captivating illustrations, stunning footage and interviews with leading climate scientists as well as support from Greta Thunberg and the Dalai Lama, 'Earth Emergency' adds the missing piece of the climate puzzle.
Narrated by Richard Gere, the film examines four of the major warming feedback loops threatening our planet: Forests, Permafrost, Albedo and Atmosphere.

The meteoric rise of renewable energy has consequences for our electricity supply. While coal and gas fired power stations can generate electricity whenever you need it, renewables are intermittent by nature. So we need a backup plan for when the wind stops or the sun goes down.
All over the world, engineers and scientists are racing to solve one key problem; how to safely and efficiently store electricity at a huge scale but at a low cost. The quest is producing some truly remarkable ideas and this episode details three of them.