Classical Athens was a powerful city-state, a centre for the arts, learning and philosophy, home of Plato's Academy and Aristotle's Lyceum, and it is widely referred to as the cradle of Western civilization and the birthplace of democracy, largely due to the impact of its cultural and political achievements during the 5th and 4th centuries BC on the rest of the then known European continent. The heritage of the classical era is still evident in the city, represented by a number of ancient monuments and works of art, the most famous of all being the Parthenon, widely considered a key landmark of early Western civilization. The city also retains a vast variety of Roman and Byzantine monuments, as well as a smaller number of remaining Ottoman monuments projecting the city's long history across the centuries. Athens is home to two UNESCO World Heritage Sites, the Acropolis of Athens and the medieval Daphni Monastery.
