Scientists revisiting a famous Neanderthal cave in France are investigating one preserved kneeprint deep inside the dark cavern as researchers attempt to understand who, or what left it behind. A clay impression discovered deep inside Bruniquel cave in south-west France could be the kneeprint of a Neanderthal who helped build strange circular structures. Preserved beneath a layer of calcite, the mark is now drawing attention from researcher... [4005 chars]