Brian travels across the US and encounters some astonishing creatures that reveal how the senses evolved. It is a story that takes him through life's journey, from single-celled organisms to sentient beings.

In this final episode we complete our journey, travelling back from the March equinox to the end of June. Kate Humble is in the Arctic at a place where spring arrives with a bang, whilst Helen Czerski chases a tornado to show how the earth's angle of tilt creates the most extreme weather on earth.

Andrew Graham-Dixon travels to Istanbul to immerse himself in the tumultuous world of the Byzantine Empire. He decodes the iconography of the art of the period and explains its continuing relevance.

Andrew Graham-Dixon continues his exploration of German art by looking at the tumultuous 19th and early 20th centuries, and how artists were at the forefront of Germany's drive to become a single nation. Andrew travels to the north and the coastal town of Griefswald, the birthplace of Caspar David Friedrich, the most influential of the German Romantics, to discover how the Baltic coast impacted his mysterious paintings of the German landscape. He also visits Berlin and explores the art of the powerful Prussian state, which would spearhead the unification of Germany in 1871. The episode ends with the outbreak of World War I and the attempts of the artists Franz Marc and Otto Dix to rationalise the catastrophic experiences of the world's first technological war, a war driven by the Prussian innovations.

Oil theft has become big business in Nigeria. Travel to this Africa's oil-producing region to meet with oil thieves, and follows one farmer's attempt to sue a foreign oil company for poisoning his family's land. The lethal combination of gangs and guns has turned Chicago into a war zone. Visit the city's most dangerous areas.

The tale of one of China's most famous dynasties begins with the amazing story of Hongwu, a peasant rebel who founded one of greatest eras in Chinese history. The film takes us to his great capital Nanjing, with its 21 miles of walls, each brick stamped with the name of the village that made it. Following the trail, we go to the Bao family village and see the villagers act a Ming murder story.
Like many authoritarian states, the Ming were obsessive about architecture. We see the giant fortifications of the Great Wall, the ritual enclaves of the Forbidden City in Beijing and travel with bargeman Mr Hu down the Grand Canal, China's great artery of commerce right up to the present day. We then hear about Admiral Zheng He's voyages to Africa and the Gulf decades before Columbus, watch the construction of an ocean-going wooden boat 250ft long, and hitch a ride on a replica Ming junk in the South China Sea.
As state prosperity grew, so did a rising middle class. Wood looks at Ming culture in Suzhou, the 'Venice of China'. Staying in a merchant's house, he discovers the silk, ceramic and lacquer-making industries, and visits one of the most beautiful gardens in the city. Then on to Macao and the arrival of Jesuit missionary Matteo Ricci, who hoped to convert China to Christianity. In the cathedral in Beijing, we learn more about these fateful exchanges with the west. Finally in Shaoxing, we visit the house of the 'Ming Proust' and at grassroots the Zhao family in Fujian where the film ends in an elegiac mood with the fall of the Ming in 1644.