Tournai is considered to be one of the most important cultural sites in Belgium. The mixed Romanesque- and Gothic-style cathedral of "Notre Dame de Tournai" and the belfry, considered the oldest in Belgium, have been designated by UNESCO as World Heritage Sites. Inside the cathedral, the "Châsse de Notre-Dame flamande", a beautifully ornate 12th-century reliquary, gives witness to Tournai's wealth in the Middle Ages. Other places of interest are the 13th-century Scheldt bridge ("Pont des Trous") and the main square ("Grand Place"), as well as several old city gates, historic warehouses, and a variety of museums.