Acropolis is Greek for "high city." The closest English translation of the word "acropolis" is Citadel. Centuries ago, when people chose a place to settle, they also chose a site on the highest ground to build defenses against invading armies.One of the most famous of these defense positions is the Acropolis of Athens, which is so well known, it is simply called, "the Acropolis." Even though the word is Greek, it can be applied to any such defense structure, no matter where it is located. Rome's acropolis, like many others in various cities, became the center of the city, with all of Rome surrounding it at its base. Other famous acropolis sites are the Rock of Cashel in Ireland and Castle Rock in Scotland.