"The Ark of the Covenant" and the "Holy Grail" are the most famous lost artefacts in history, but everything from armies and cities, to plays and poems, have been swallowed up by the sands and seas of history, leaving behind only legends to tantalise and inspire archaeologists and treaure hunters alike. Is there any evidence of El Dorado and Sodom and Gommorah? Have we really lost plays by Shakespeare and dialogue from Aristotle? Will divers ever find the Golden Hide or Columbus' fleet? And where are the resting places of a host of bodies, from Ghengis Khan to George Mallory?