Columbia subject headings:
City walls--Italy--Genoa.
Fortification--Italy--Genoa.
Genoa (Italy)--Fortifications, military installations, etc.
Harvard subject headings:
Princeton subject headings:
Fortification--Italy--Genoa.
Genoa (Italy)--Buildings, structures, etc.
Genoa (Italy)--Fortifications, military installations, etc.
Genoa (Italy)--History.