In its present form, it is an outstanding example of a fortified medieval city with an enormous defensive system developed mainly in the 13th century. The enclosure is surrounded by moats and the two main entrances to the fortified city, the Porte Narbonnaise and the Porte de l'Aude, are particularly elaborate. Criterion (ii): The fortified city of Carcassonne owes its exceptional importance to the restoration work undertaken during the second half of the 19th century by Viollet-le-Duc, who strongly influenced the evolution of conservation principles and practices. Criterion (iv): The city of Carcassonne is an excellent example of a fortified medieval city whose enormous defensive system was built on ramparts dating from late antiquity. IntegrityThe fortifications of Carcassonne, as well as the castle and the cathedral, are imposing monuments which reflect in an exceptionally complete way the structure of a medieval fortified city.