The most powerful landmark of St. Goar is Rheinfels Castle. It is the largest and one of the most magnificent castle ruins on the Rhine - equally important for the castle architecture of the Counts of Katzenelnbogen in the 14th century as well as for the castle and fortress construction of the 16th to 18th century Landgrave of Hesse-Kassel. Immerse yourself in the Middle Ages, explore fortifications, towering towers and halls and passageways cut into the rock.