Ewan and Charley make their way to Peru from Bolivia, and the scenery is just beautiful. Ewan wanted to visit Machu Picchu since he was a kid and decides to show the world the Incan citadel set high in the Andes Mountains. Next up, they make their way to the Cutivireni, a community of Ashaninka people in the Amazon rainforest, with its carbon program to limit the magnitude or rate of global warming and its related effects.

Planets beyond our solar system are known to astronomers as exoplanets. They are at trillions of miles from Earth and yet, it might be possible to detect a faint signature of life in them. From the light of the stars they orbit that passes through the atmosphere of an exoplanet, it is possible to capture the chemical fingerprint of the elements in that atmosphere.
The fictional world Eden is orbiting not one star, but two. The light from its twin stars powers photosynthesis, pumping more oxygen into the atmosphere than in Earth, allowing life to thrive. Grazers are constantly alert to danger, because the canopy is home to predators perfectly evolved to live among the trees. In Episode 3, another topic are fungi and the role they could play on exoplanets. Ecologist Thomas Crowther talks about the role mycelial networks play in the Rothiemurchus forest in Scotland.

The third assault on the tattered remains of Roman civilization came from even further North, where the melting glacial ice had created immense sheltered fjords, leaving its inhabitants little choice but the sea. These fearless navigators understood that dominion over the oceans was the key to their ambitions.
Where the Romans expanded incrementally, the Vikings adopted a bolder, more aggressive approach. So was it the Dark Age which failed Europe, or the stifling uniformity of the great Roman experiment? Were the lost tribes more victim than failure? Richard Rudgley will hope to shed new light on the real secrets of the so-called Dark Age.

Grasslands cover one quarter of all land and support the vast gatherings of wildlife, but to survive here animals must endure the most hostile seasonal changes on the planet. From Asia's bizarre-looking Saiga antelope to the giant anteaters of Brazil, grassland animals have adapted in extraordinary ways to cope with these extremes. In the flooded Okavango, lions take on formidable buffalo in epic battles, on the savannah bee-eaters take advantage of elephants to help catch insects and, on the freezing northern tundra, caribou embark on great migrations shadowed by hungry Arctic wolves.

Nicholas felt enormous pressure to continue the dynasty and expand the empire. He saw his opportunity in the Far East. This brought him into conflict with a rising power, Japan. Russia's disastrous war against Japan prompts civil unrest. The birth of Prince Alexei is incredibly important. He's the long-awaited son that they had hoped so much for. But when Alexei is diagnosed with haemophilia, Siberian mystic Rasputin steps in. He's very good at realizing when something is open that will enable him to increase his power and wealth. The pressure of keeping the secret of Alexei's illness affects the political decisions that Nicky and Alix made for the rest of their reign.

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