The Acropolis of Athens is the most striking and complete ancient Greek monumental complex still existing in our times. It is situated on a hill of average height (156m) that rises in the basin of Athens. Its overall dimensions are approximately 170 by 350m. The hill is rocky and steep on all sides except for the western side, and has an extensive, nearly flat top. Strong fortification walls have surrounded the summit of the Acropolis for more than 3,300 years. The first fortification wall was built during the 13th century BC, and surrounded the residence of the local Mycenaean ruler. In the 8th century BC, the Acropolis gradually acquired a religious character with the establishment of the cult of Athena, the city’s patron goddess. The sanctuary reached its peak in the archaic period (mid-6th century to early 5th century BC). In the 5th century BC, the Athenians, empowered from their victory over the Persians, carried out an ambitious building programme under the leadership of the great statesman Perikles, comprising a large number of monuments including the Parthenon, the Erechtheion, the Propylaia and the temple of Athena Nike. The monuments were developed by an exceptional group of architects (such as Iktinos, Kallikrates, Mnesikles) and sculptors (such as Pheidias, Alkamenes, Agorakritos), who transformed the rocky hill into a unique complex, which heralded the emergence of classical Greek thought and art. On this hill were born Democracy, Philosophy, Theatre, Freedom of Expression and Speech, which provide to this day the intellectual and spiritual foundation for the contemporary world and its values. The Acropolis’ monuments, having survived for almost twenty-five centuries through wars, explosions, bombardments, fires, earthquakes, sackings, interventions and alterations, have adapted to different uses and the civilizations, myths and religions that flourished in Greece through time.