Columbia subject headings:
City walls--Italy--Pompeii (Extinct city)
Pompeii (Extinct city)
Harvard subject headings:
Excavations (Archaeology)--Italy--Pompeii (Extinct city)
Fortification, Roman--Italy--Pompeii (Extinct city)
Pompeii (Extinct city)
Princeton subject headings:
Pompeii (Extinct city)--Fortifications, military installations, etc.