Humans trod the landscape of North America thousands of years earlier than previously thought, according to new research that confirms the antiquity of fossilized footprints at White Sands National Park in New Mexico using two further dating approaches.
Given that the only record we have of them are some footprints in the middle of a desert, I think finding their tools is going to be a little more challenging.
More than anything, though, I think this demonstrates just how non-permanent human civilisation is.