This emblematic 14-sided tower stands on a 2.5 to 3 m high circular foundation, in which many authors have suggested the remains of a Carolingian chapel. The tower is said to have actually been the keep of a castle built by the Counts of Luxembourg in the 16th century, corresponding to the size of the present castle courtyard.
It served successively as a residence and last refuge in the event of an attack, as an armory, a prison, and finally, in 1905, as a museum.