Turkana stone beads tell a story of herder life in a drying east Africa 5,000 years ago

On the shores of Lake Turkana in east Africa, about 5,000 to 4,000 years ago, pastoralists buried their dead in communal cemeteries that were marked by stone circles and pillars. The north-west Kenya "pillar sites" were built around the same time as Stonehenge in the UK. But these places have a different story to tell: about how mortuary traditions reflect people's environments, behaviors and reactions to change.