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.

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."

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."

When Japan’s military expansion in the Pacific reaches its fever pitch, Roosevelt is forced to act. By cutting off oil supplies, he hopes to force Japan to back down. But far from sedating their imperial expansions, he pushes them to take one of the greatest gambles in military history – taking their entire striking fleet 4000 miles across the Ocean to attack the American Pacific fleet in Pearl Harbor. It’s a huge gamble, and if it goes wrong, it will spell suicide for Japan.

For the past century, Russian history has also been the history of its security services. They were used by the Soviet state to crush dissent. Millions suffered at their hands. Mass executions, secret wars, spies capable of stealing the atomic bomb, poisoning scandals all add up to the most extraordinary and dangerous security network the world has ever known. But even today, the security network is arguably stronger than ever. This is the History of the KGB, told through its veterans and its victims.
Founded in 1917, Cheka was the predecessor organization of the KGB. Set up as a 'temporary' measure by Lenin, unknown number of Soviet citizens would die at the hands of the secret services as internal dissents in the 1920s. An inglorious chapter is the "Great Terror" phase, when millions of Soviet citizens were convicted and executed in mock trials under Stalin's rule in the 1930s. Outside the Soviet Union, during the WWII they were busy infiltrating German High Command, British Intelligence and America's Manhattan Project. The Cold War had begun in earnest.