5/5 Dr Alice Roberts investigates the possible routes taken by humans to reach the Americas.
4/5 Dr Alice Roberts looks at our ancestors' seemingly impossible journey to Australia.
3/5 Looking at how our species coped with the rival Neanderthals and the Ice Age.
2/5 Dr Alice Roberts travels to northern Siberia to learn how hunter-gatherers survived there.
1/5 Alice Roberts travels to Africa in search of the birthplace of the first people.