French archeologist Madeleine Colani began excavating at the Jar sites in the 1930s, most of the urns had been looted, although she did find bronze and iron tools as well as coloured glass beads, bronze bracelets and cowrie shells. Colani theorized that the jars were funerary urns, originally holding cremated remains. More recent discoveries have revealed underground burial chambers, further supporting Colani's theory. Because of the great age of the jars and the unsolvable mystery of their origin, they have perhaps become famous beyond their aesthetic merits.