Columbia subject headings:
Architecture, Byzantine--Greece--Thessalonikē--Congresses.
Byzantine antiquities--Greece--Thessalonikē--Congresses.
Citadel (Thessalonikē, Greece)--Congresses.
Harvard subject headings:
Eptapyrgion (Thessalonikē, Greece)--History--Exhibitions.
Fortification--Greece--Thessalonikē--Exhibitions.
Greece--Antiquities, Byzantine--Exhibitions.
Thessalonikē (Greece)--Antiquities, Byzantine--Exhibitions.
Thessalonikē (Greece)--Buildings, structures, etc.--Exhibitions.
Princeton subject headings:
Eptapyrgion (Thessalonikē, Greece)--History--Exhibitions.
Fortification--Greece--History--Exhibitions.
Greece--Antiquities, Byzantine--Exhibitions.
Thessalonikē (Greece)--Antiquities, Byzantine--Exhibitions.
Thessalonikē (Greece)--Buildings, structures, etc.--Exhibitions.