When did the first people arrive here? What did they look like? How did they survive? Who were the Neanderthals?

Chris Stringer takes us back to when it was so tropical we lived here alongside hippos, elephants and sabre-toothed tigers or to times so cold we hunted reindeer and mammoth, and to others even colder when we were forced to flee a wall of ice. Here is the incredible truth about our ancestors' journey over millennia - and a glimpse of the future to see how it might continue.