This episode explores how scientists delved ever deeper into the world of the cell, seeking to reveal the magic ingredient that can spark a bundle of chemicals into life. Their discoveries have brought us to the brink of being able to create life for ourselves.

Humans are so clever they’ve built their own habitat, designed to keep wild nature out. Yet as we discover the urban environment is totally dependant on the natural world. Over the three years of filming for Human Planet, the teams have spent time with over seventy different communities in countries across the planet. Despite seeing many different ways of living, there are some aspects of family life that remain the same whether you live in a tree house in West Papua, or a brick house in Bolton. These similarities became very clear when the urban team went to film on a rubbish dump in Kenya. Here on the Kibarani dump on the outskirts of Mombasa, Ali, Ashe and their family live and survive amongst the rubbish, and even here, just like anywhere on the planet, everything stops for a nice cup of tea!

Marcus du Sautoy uncovers the patterns that explain the shape of the world around us. Starting at the hexagonal columns of Northern Ireland's Giant's Causeway, he discovers the code underpinning the extraordinary order found in nature - from rock formations to honeycomb and from salt crystals to soap bubbles. Marcus also reveals the mysterious code that governs the apparent randomness of mountains, clouds and trees and explores how this not only could be the key to Jackson Pollock's success, but has also helped breathe life into hugely successful movie animations.

David Attenborough reveals the surprising truth about the cold-blooded lives of reptiles and amphibians. These animals are as dramatic in combat, as colourful in their communication and as tender in their parental care as any other animals. Join giant courting crocodiles, jousting tortoises and bright red sumo-wrestling frogs in their sophisticated, solar-powered lives.

Years after Bruce Lee's mysterious death is attributed to the 'Lee Family Curse', his son Brandon's life was cut short due to a tragic on-set accident during the making of The Crow. As Lee had finished most of his scenes before his death, the film was completed through script rewrites, a stunt double, and digital effects. The Crow is dedicated to Brandon Lee and his fiancée, Eliza Hutton.

Dr Nigel Spivey explores how art influences life by tracing the development of the image from cave paintings to our modern obsession with images. Dr. Spivey begins his investigation by travelling to the Cave of Altamira near the town of Santillana del Mar in Cantabria, Spain, where in 1879 a young girls exclamation of 'Papa, look, oxen!' to her father, local amateur archaeologist Marcelino Sanz de Sautuola, is explained to have meant that Maria had just become the first modern human to set eyes on the first gallery of prehistoric paintings ever to be discovered.