As a coherent picture emerges, however, new mysteries arise. It is looking likely that our species appeared far earlier than previously suspected - and remained in Africa for tens of thousands of years before going global. It could be said that humans were all dressed up and going nowhere.
Why the delay? Yet when our ancestors finally flocked onto the world stage, their spread was remarkably rapid. What caused them to explode out of Africa when they did? What circumstances suddenly allowed those early humans to smash down their boundaries like no species before or since?