Columbia subject headings:
Harvard subject headings:
Ērakleion (Greece)--Buildings, structures, etc.
Fortification--Greece--Ērakleion--History.
Harbors--Greece--Ērakleion--History.
Shipyards--Greece--Ērakleion--History.
Ērakleion (Greece)--History.
Princeton subject headings:
Ērakleion (Greece)--Buildings, structures, etc.
Ērakleion (Greece)--History.
Fortification--Greece--Hērakleion--History.
Harbors--Greece--Hērakleion--History.
Shipyards--Greece--Hērakleion--History.