Columbia subject headings:
City walls--Conservation and restoration.
City walls--Italy--Milan--History.
Gates--Conservation and restoration.
Gates--Italy--Milan--History.
Milan (Italy)--Antiquities.
Porta Nuova (Milan, Italy)--History.
Harvard subject headings:
Princeton subject headings:
City walls--Italy--Milan.
Gates--Italy--Milan.
Milan (Italy)--Buildings, structures, etc.
Sculpture, Italian--Italy--Milan--Conservation and restoration.