An exceptional historical city, in the sense that it preserves the actual remains of medieval Crusader buildings, beneath the fortified Muslim city built in the 18th and 19th centuries. The remains of the Crusader city of Acre, below and above the street level of the street, provide an extraordinary picture of the urban route and of the capital structure of the Kingdom of Jerusalem. Today’s Acre is an important example of a walled Ottoman city, with typical urban foundations, such as a fortress, mosques, khans and hammams, built in part on top of the Crusader buildings. In 2001, ancient Acre was declared a World Heritage Site by UNESCO.