A castle, or at least its ruins, worth visiting is castle Valkenburg that has a history going back to the 11th century. The ruins are the remains of the 3rd castle build on this location.
You’ll understand how impressive that is when seeing the remains of the hall of knights and defense towers.
In addition, in 1937 they discovered secret underground passage ways that you can enter during your trip and will lead you to the Fluweelengrot (Velvet cave). Thanks to the various wall decorations, statues and chapel, for a while there you’ll be able to imagine what it must have been like living there in the times of knights. Did you know that a large part of the stones of the castle were used to rebuild Valkenburg after the fire in 1773?
Video Castle Ruins Valkenburg