Poertoren, Medieval gunpowder tower at Minnewater, Bruges, Belgium.

The Poertoren is a round, three-storey brick tower about 18 metres high and 8 metres in diameter, with walls roughly 1.3 metres thick, standing at the east end of Begijnenvest by the Minnewater bridge in Bruges. Its lower room has a cross-rib vault on natural-stone corbels, and a small polygonal stair turret with slit windows adjoins the northwest side.

Jan Van Oudenaarde built the freestanding tower in 1397-1398 as part of a water gate on the Minnewater; a second, lower tower on the opposite bank was later demolished. From 1477 the tower stored the city's gunpowder, and in 1665 it briefly served as a fulling mill. It was used as an ice cellar until 1785, then restored in 1989-1991 by architect A. Cottyn.

The tower shows how Bruges adapted its structures over time: from military defense to practical storage for ice in warmer months. This shift reveals how the city responded to different needs across centuries.

The tower sits beside the Minnewater bridge and serves as a good starting point for a walk along the former city fortifications. From here you can explore the historic paths of the old walls and discover the Minnewater area.

The tower's brickwork mixes stones of different sizes, suggesting the city supplied recycled bricks to contractor Jan Van Oudenaarde. The octagonal stair turret uses Flemish bond, while the main round wall is laid in standing bond. The lower room's cross-rib vault rests on a Brabant limestone keystone carved with floral motifs.