Eltz Castle Burg Eltz is a medieval castle nestled in the hills above the Moselle River between Koblenz and Trier , Germany . It is still owned by a branch of the same family that lived there in the 12th century , 33 generations ago . The Rübenach and Rodendorf families ' homes in the castle are open to the public , while the Kempenich branch of the family uses the other third of the castle . The Palace of Bürresheim ( ) , the Castle of Eltz and the Castle of Lissingen are the only castles on the left bank of the Rhine in Rhineland - Palatinate which have never been destroyed . Location . The castle is surrounded on three sides by the Elzbach River , a tributary on the north side of the Moselle . It is situated on a 70 m rock spur , on an important Roman trade route between rich farmlands and their markets . Description . The castle is a so - called " Ganerbenburg " , or castle belonging to a community of joint heirs . This is a castle divided into several parts , which belong to different families or different branches of a family ; this usually occurs when multiple owners of one or more territories jointly build a castle to house themselves . Only a very rich medieval European lord could afford to build a castle on his land ; many of them only owned one village , or even only a part of a village . This was an insufficient base to afford a castle . Such lords lived in a knight ' s house , which was a simple house , scarcely bigger than those of his tenants . In some parts of the Holy Roman Empire of the German Nation , inheritance law required that the estate be divided between all successors . These successors , each of whose individual inheritance was too small to build a castle of his own , could build a castle together , where each owned one separate part for housing and all of them together shared the defensive fortification . In the case of Burg Eltz the family comprised three branches and the existing castle was enhanced with three separate complexes of buildings . The main part of the castle consists of the family portions . At up to eight stories , these eight towers reach heights of between 30 and 40 meters . They are fortified with strong exterior walls ; to the yard they present a partial framework . About 100 members of the owners ' families lived in the over 100 rooms of the castle . Platteltz , a Romanesque keep , is the oldest part of the castle . In 1472 the Rübenach house , built in the Late Gothic style , was completed . Remarkable are the Rübenach Lower Hall , a living room , and the Rübenach bedchamber with its opulently decorated walls . Between 1490 and 1540 , the Rodendorf house was constructed , also in Late Gothic style . It contains the vaulted " banner - room " . The Kempenich houses were finished about 1530 . Every room of this part of the castle could be heated ; in contrast , other castles might only have one or two heated rooms . From 1965 to 1992 , an engraving of Burg Eltz was used on the German 500 Deutsche Mark note . In fiction . The starting events of " Le Feu de Wotan " , a Belgian bande dessinée in the Yoko Tsuno series , take place in Burg Eltz . The Castle was also used as the exterior for the fictional American military insane asylum in the 1979 William Peter Blatty movie , " The Ninth Configuration " , starring Stacy Keach .