The remains of the Castle can be visited
Langensteinbach

The castle ruin Langensteinbach, also known as Römerturm, is a medieval structure in Karlsbad-Langensteinbach. Its uniqueness lies in the well-preserved tower ruin and the surrounding fortification remains.
History+
The origins of Langensteinbach Castle date back to 1100, when it was built as a tower castle. The tower had foundation walls 3.5 meters thick and presumably reached a height of 35 meters. After partial destruction by fire, the tower was rebuilt. To protect against siege engines, a moat was dug directly adjacent to the foundations. The castle was abandoned as early as the 13th century, as evidenced by ceramic finds from the 1970s.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: https://commons.wikimedia.org/wiki/File:Burgruine-Langensteinbach.jpg
This description draws on the facts documented in the linked Wikipedia article; Wikipedia content is licensed under CC BY-SA 4.0. Wording and editing: Mobile History.
Location: 48.9058, 8.4971