East Africa is a land which is constantly changing. To survive here, creatures must be able to deal with unpredictable twists and turns - wet turning to dry, feast to famine, cold to hot - no matter how hostile it becomes. From dense forests to snow capped peaks, steamy swamps and endless savannah, this unique and varied land is also a haven for life, supporting large animals in numbers found nowhere else on Earth. But away from the familiar, forever-travelling herds, there are a huge cast of other characters - lizards that steal flies from the faces of lions, vast dinosaur-like birds who stalk catfish through huge wetlands, and an eagle who risks everything on the arrival of ten million bats from a far off rainforest.

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.