The remains of the Castle can be visited
Schwarzwald Castle

The Schwarzwald Castle Ruin, a former high medieval fortification, is on a narrow mountain ridge above the Schwarzwald district of Luisenthal in Thuringia. Initially, it served to monitor a military and trade route and later developed into an administrative center.
History+
The first documented mention of Schwarzwald Castle occurred in 1290 at the Imperial Diet in Erfurt. Until 1302, it was owned by the Counts of Kevernburg, then briefly by the Counts of Orlamünde, and subsequently by the Counts of Schwarzburg. Around 1367, an attempt by the city of Erfurt to acquire the castle to secure its trade routes failed.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://www.wehrbauten.de/thread.php?threadid=589&sid=9b2b210ff3d27b7a80b9c70dbb4777c0
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: 50.7686, 10.7315