Pompeii: Plaster cast
The ash fall during the eruption of Vesuvius buried the town and covered many of its inhabitants.  In the 1860s, Italian archaeologist Giuseppe Fiorelli discovered that mounds of ash often contained the moulds of those who perished in the catastrophe.  Plaster was poured into the mounds and, when hardened, left the casts of the victims - much like that of the man in this picture who might have died trying to filter the noxious fumes of the eruption.

This method of retrieving the shapes of Vesuvius' victims, now known as the "Fiorelli Method",  has even been extended to recreating the forms of furniture, doors and shutters on Pompeiian buildings.