History’s greatest mysteries: what caused the medieval ‘dancing plague’?

On several occasions from the 14th to 16th centuries, hundreds of people in central Europe began moving their bodies in a strange uncontrollable fashion – often for days on end. What was behind this unusual behaviour? In the final episode of this series of History’s Greatest Mysteries, medieval historian Helen Carr describes the events of the ‘dancing plagues’ and considers the various explanations that have been put forward so far.