Our ancient ancestors weren’t fumbling with crude rocks. A groundbreaking archaeological discovery in Kenya reveals they had mastered a stone tool technology so effective that they stuck with it for ...

Our prehistoric human ancestors relied on deliberately modified and sharpened stone tools as early as 3.3 million years ago. The selection of rock type depended on how easily the material could be ...

Ailsa Chang speaks with David Braun, an archeologist, about his team's discovery of a site in Kenya that suggests human ancestors built tools continuously much earlier than previously thought. So when ...