Alastair Sooke charts the decline and fall of the Roman Empire through some of its hidden and most magical artistic treasures. On a trip to Leptis Magna in Libya, shortly after the overthrow of Colonel Gaddafi, he finds one of the best preserved Roman cities in the world and the cradle of later Roman art. Sooke discovers glorious mosaics that have never been filmed before, but also finds evidence of shocking neglect of Libya's Roman heritage under the Gaddafi regime