Anuradhapura is one of the ancient capitals of Sri Lanka, famous for its well-preserved ruins of ancient Lankan civilization. From the 4th century BC, it was the capital of Sri Lanka until the beginning of the 11th century AD. During this period it remained one of the most stable and durable centers of political power and urban life in South Asia. The ancient city, considered sacred to the Buddhist world, is today surrounded by monasteries covering an area of over sixteen square miles (40 km²). Anuradhapura is also significant in Hindu legend as the fabled capital of the Asura King Ravana in the Ramayana.The city is now UNESCO World Heritage Site.