Carcassonne (French; Latin: Carcaso) is a fortified French town in the Aude department, of which it is the prefecture, in the Region of Occitanie. Inhabited since the Neolithic period, Carcassonne is located in the Aude plain between historic trade routes, linking the Atlantic to the Mediterranean sea and the Massif Central to the Pyrénées. Its strategic importance was quickly recognized by the Romans who occupied its hilltop until the demise of the Western Roman Empire and was later taken over in the fifth century by the Visigoths who founded the city. Its strategic location led successive rulers to expand its fortifications until the Treaty of the Pyrenees in 1659. The city is famous for the Cité de Carcassonne, a medieval fortress restored by the theorist and architect Eugène Viollet-le-Duc in 1853 and added to the UNESCO list of World Heritage Sites in 1997. Consequently, Carcassonne relies heavily on tourism but also counts manufacture and wine-making as some of its other key economic sectors.