The Schelmentoren is a medieval defensive tower in the centre of Heerlen, and one of the oldest surviving structures in the city. Built in the 14th or 15th century as a residential watchtower for a local noble family, it served as a dwelling and refuge during a period when the region between the counties of Gelre and the duchy of Jülich was frequently contested.
The tower stands about 16 metres tall and is constructed of local marl stone — the soft yellow-white limestone quarried extensively across South Limburg and used in most of the older buildings in the region. It is now surrounded by the modern city but gives a useful sense of Heerlen's pre-industrial history before the coal mines transformed everything.
The exterior can be viewed at any time; occasional events are held inside.