Ancient Greek fortifications

thumb|upright=1.5|Acropolis of Athens in Athens, Greece An acropolis was the settlement of an upper part of an ancient Greek city, especially a citadel, and frequently a hill with precipitous sides, mainly chosen for purposes of defense. The term is typically used to refer to the Acropolis of Athens, yet nearly every Greek city had an acropolis of its own. The term derives from the homonymous Greek word "Ακρόπολις", composed from "akron" (ἄκρον), which means "top", and "polis" (πόλις), which means "city".

castle in Syracuse, Italy

defensive structures around Chania, Crete, Greece