Elgin Marbles

These are a set of huge finely carved marble spheres, of great historical antiquity, which were exported from Ephebe to Ankh-Morpork in unexplained and possibly dubious circumstances by Mr Elgin, then a senior member of the Guild of Trespassers. Now believed to be in a basement of the Royal Art Museum for "safekeeping", the Ephebian government makes regular strong demands for their return.