This is the oldest belfry in Belgium, the lower part of which dates from the 12C. The base was reinforced by polygonal turrets in 1294 and the upper sections were rebuilt a century later, following a fire which broke out in 1391. Until 1817, several of the rooms were used as a prison. The first floor offers a fine view of the cathedral, and the viewpoint from the top of the tower (70m) takes in the city. The 44-chime carillon is used for numerous concerts. The belfry is a UNESCO World Heritage site.