It is a mysterious artefact found in Lepenski Vir, a Neolithic village or, perhaps, a necropolis-sanctuary, on the Serbian side of the Danube. It is 7000 years old and nobody knows its purpose. It has holes drilled at each end and perhaps a stick was passed through them to rotate the stone. But this is only a supposition. It has horizontal and vertical lines inscribed on its surface, a kind of map of the world divided into meridians and parallels. Most of the sections contain signs whereas the others are completely empty.

What is this ancient stone sphere? And what was it used for?