Explore the breathtaking extremes of our planet in this captivating episode. Journey through the vast Hang Son Doong cave in Vietnam, the largest on Earth. Witness the resilience of life in harsh conditions, marvel at the adaptation strategies of species like the blind cave fish and the enduring Arctic wolf pack. In the Arctic, observe the strategic hunt of wolves preying on musk oxen, a dance as old as the Ice Age. In the French Alps, the struggle for mating among common frogs unfolds, showcasing the urgency and challenges faced by cold-blooded animals. Witness the social dynamics of Barbary macaques in the cedar forests of the Atlas Mountains, where survival hinges on social bonds. The forests of Mexico, home to millions of monarch butterflies that huddle for warmth, illustrates the fragility and beauty of nature.
Discover how fire shapes ecosystems in South Africa's fynbos and Northern Australia, crucial for the survival of species like the golden-shouldered parrot. The documentary poignantly addresses the impact of changing climates and human intervention on wildlife, from the endangered elephants of Amboseli, Kenya, to the secretive snow leopards of the Gobi Desert. This episode offers a profound glimpse into the extraordinary adaptations and challenges faced by wildlife across the globe, reminding us of the delicate balance and beauty of life on Earth.

In the fourth part of the series, Diarmaid MacCulloch makes sense of the Reformation, and of how a faith based on obedience and authority gave birth to one based on individual conscience. He shows how Martin Luther wrote hymns to teach people the message of the Bible, and how a tasty sausage became the rallying cry for Swiss Reformer Ulrich Zwingli to tear down statues of saints, allow married clergy and deny that communion bread and wine were the body and blood of Christ.

In the fourth episode of the series, Commodus defeats his sister's coup but withdraws from governing, allowing others to amass power while he engages in an affair and banishes his wife.

The unearthing of a gruesome grave filled with thousands of skeletons at the beach of Kamakura in Japan could be about to unlock the true extent of the merciless violence and mystery surrounding the true origins of one of the most feared and revered warriors of all time: the Samurai.
In the Middle Ages, Kamakura was the capital of Japan. The 'Shogun', a kind of aristocratic military dictator, ruled here. This shogunate ended in 1333 with the Battle of Kamakura. A drastic event in Japanese history, because this resulted in not only political, but also social, philosophical and technical innovations. The remains of the samurai warriors who fell near Kamakura now provide scientists with detailed insights into the time of the Kamakura shogunate and the bloody conflict between the shogun and the emperor.
The chilling burial ground dates back to 1333. Kamakura was one of the most heavily fortified regions of Japan. When the Emperor became angered by the growing powers of the ruling Hojo family, he sought to retake control of the region, setting the stage for a war that would change the shape of the nation. Among over 4000 sets of remains, six have a unique story to tell: the husband and wife involved in a sword fight to the death; the warrior monk; a peasant boy soldier; and members of the ruling Hojo family, captured and decapitated, with their heads displayed as trophies of victory. These remains reveal the secrets of the Samurai, their ferocious fighting skills and their merciless killing techniques.

American troops launch widespread 'search and destroy' operations; body count, not territory, becomes the measure of success in Vietnam. Charles Brown fights for survival on the bloody slopes of Hill 875 and at home, the American public begins to question U.S. military strategy.

Ten years after waging a bloody campaign to gain control over his own province, powerful samurai warlord Oda Nobunaga has seized much of Central Japan, including the nation’s capital, Kyoto. Now, driven by a towering ambition, he dreams of crushing the powerful clans who still oppose his rule. And for the first time in over a century, uniting all of Japan under one banner. But Nobunaga’s legendary brutality has caused widespread anger. Across the nation, powerful enemies now plot his demise.