This week Neil MacGregor has been looking at objects from Japan, Britain, Java and central Europe, exploring the great arcs of trade that connected Africa, Europe and Asia a thousand years ago. Today he sifts through a selection of broken pots, found on a beach in East Africa, to see what they might tell us. Smashed pottery, it seems, can be astonishingly durable and can offer powerful historical insights. These ceramic bits - in a variety of glazes and decorations - were found on the island of Kilwa Kisiwani off Tanzania. Neil uses the fragments to tell the story of a string of thriving communities along the East African coast with links across the Indian Ocean and beyond. The historian Bertram Mapunda and the writer Abdulrazak Gurnah describe the significance of these broken pieces and help piece together the great cross-cultural mix that produced the Swahili culture and language. Producer: Anthony Denselow.