The Castle can be visited
Thurandt Castle

Thurandt Castle, a prominent spur castle, stands on a slate spur high above the Moselle village of Alken. It is known for its unique dual-castle layout, once administered jointly by two archbishoprics.
History+
The first documented mention of a structure at this location dates back to 1209. Count Palatine Heinrich I the Long presumably had the fortification built between 1198 and 1206 to secure Welf interests in the Moselle region. After his death in 1214, the castle passed to the Wittelsbachs but was also claimed by the Archbishops of Cologne and Trier. In 1216, Engelbert I of Cologne forcibly captured the castle. Upon its return to the possession of the Counts Palatine, the castle became a nuisance to the region due to the robber knight Berlewin, leading to a siege in 1246 by Arnold II of Isenburg and Konrad von Hochstaden.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: © BraCom (Bram)
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: 50.2482, 7.4529