The Ancient Citadel, or ACROPOLIS, is an ancient citadel located on a high rocky outcrop above the city of Athens. It was built in the 5th century BC and served as the ceremonial and political center of the ancient Athenian city-state. The ACROPOLIS is home to some of the most iconic monuments of ancient Greece, including the Parthenon, the Propylaea, the Erechtheion, and the Temple of Athena Nike. It is a UNESCO World Heritage Site and one of the most visited archaeological sites in the world.