Belfries of Flanders and Wallonia (1999)
Belgium

The 30 belfries in Flanders and Wallonia, invariably found in an urban setting, are imposing bell-towers of medieval origin, generally attached to the town hall and occasionally to a church. In addition to their outstanding artistic value, the belfries are potent symbols of the transition from feudalism to the mercantile urban society that played a vital role in the development of late medieval Europe. 

Here are a few examples of these belfries on both older and more recent stamps. All stamps have the correct relative proportions.