An extraordinary chapter has just been added to the story of the First Americans. Finds at a site in California suggest that the New World might have first been reached at least 130,000 years ago - more than 100,000 years earlier than conventionally thought. If the evidence stacks up, the earliest people to reach the Americas may have been Neanderthals or Denisovans rather than modern humans. Researchers may have to come to terms with the fact that they have barely scratched the surface of the North American archaeological record.