Alice travels to Africa in search of the birthplace of the first people. They were so few in number and so vulnerable that today they would probably be considered an endangered species. So what allowed them to survive at all? The Bushmen of the Kalahari have some answers - the unique design of the human body made them efficient hunters and the ancient click language of the Bushmen points to an early ability to organise and plan. Humans survived there, but Africa was to all intents and purposes a sealed continent. So how and by what route did humans make it out of Africa? Astonishing genetic evidence reveals that everyone alive today who is not African descends from just one successful, tiny group which left the continent in a single crossing, an event that may have happened around 70 thousand years ago. But how did they do it? Alice goes searching for clues in the remote Arabian Desert.

In this programme, the journey continues into Asia, the world's greatest land mass, in a quest to discover how early hunter-gatherers managed to survive in one of the most inhospitable places on earth - the Arctic region of Northern Siberia. Alice meets the nomadic Evenki people, whose lives are dictated by reindeer, both wild and domesticated, and discovers that the survival techniques of this very ancient people have been passed down through generations. Alice also explores what may have occurred during human migration to produce Chinese physical characteristics, and considers a controversial claim about Chinese evolution: that the Chinese do not share the same African ancestry as other peoples.

When our species first arrived in Europe, the peak of the Ice Age was approaching and the continent was already crawling with a rival: stronger, at home in the cold and even (contrary to their popular image) brainier than us. So how did the European pioneers survive first the Neanderthals and then the deep freeze as they pushed across the continent? Alice Roberts reconstructs the head of the 'first European' to come face to face with one of our ancestors; she discovers how art became crucial for survival in the face of Neanderthal competition; and what happened to change the skin colour of these European pioneers from black to white. Finally, spectacular new finds on the edge of Europe suggest that the first known temples may have been a spark for a huge revolution in our ancestors' way of life - agriculture.

Alice looks at our ancestors' seemingly impossible journey to Australia. Miraculously preserved footprints and very old human fossils buried in the outback suggest a mystery: that humans reached Australia almost before anywhere else. How could they have travelled so far from Africa, crossing the open sea on the way, and do it thousands of years before they made it to Europe? The evidence trail is faint and difficult to pick up, but Alice takes on the challenge. In India, new discoveries among the debris of a super volcano hint that our species started the journey much earlier than previously thought, while in Malaysia, genetics points to an ancient trail still detectable in the DNA of tribes today. Alice travels deep into the Asian rainforests in search of the first cavemen of Borneo and tests out a Stone Age raft to see whether sea travel would have been possible thousands of years ago, before coming to a powerful conclusion.

How did Stone Age people reach North and South America? Dr Alice Roberts discovers evidence for an ancient corridor through the Canadian ice sheet that may have allowed those first people through. But some very ancient finds in southern Chile seem to suggest a very different way into the Americas; an ancient human skull discovered in Brazil even points to an Australasian origin of the Americans. Could a route from Australia across the Pacific have been possible?