Wikipedia
Schelmentoren
The Schelmentoren in Heerlen is a Medieval Building that has served as a defendable living tower for the Here van Are (sometimes called the counts van Ahr-Hochstaden) and their successors. As part of the Landsfort Herle, it served as a prison tower. It is believed to be built on command of Theoderich van Are. What is certain is that the building existed in the 12th century.