Acropolis: Topic Page[Gr.,=high point of the city], elevated, fortified section of various ancient Greek cities. The Acropolis of Athens, a hill c.260 ft (80 m) high, with a flat oval top c.500 ft (150 m) wide and 1,150 ft (350 m) long, was a ceremonial site beginning in the Neolithic Period and was walled before the 6th century BCE by the Pelasgians.