Built on the Acropolis of Athens in the 5th century BCE as a temple to Athena, the Parthenon today stands in ruins. Much of the original marble that formed the roof now lies in a pile of rubble at its base, and half of the frieze is now displayed in the British Museum. Even so, it remains one of the most important surviving buildings of Classical Greece and a symbol of Athenian democracyPhoto credit: Thermos