No site in the world has been continually excavated for so long as Pompeii, the city that lay buried after being destroyed when Mount Vesuvius erupted, until its accidental discovery over 1,700 years later. Not far away lies Herculaneum; buried in the same eruption, it is less well known among tourists but just as much of a treasure trove for archaeologists and historians. There are two main reasons for this.

Firstly, the cities are well preserved. The eruption may have wiped out their inhabitants, but it also ensured that they were kept alive in historical memory, thanks to the metres of ash that shielded the ruins and remains from the elements. Historians have therefore had access to details which in other cities they can only guess at.