The remains of the Castle can be visited
Gerolstein Castle

The castle ruin of Gerolstein, also known as Löwenburg, sits on a rocky hill above the town of Gerolstein in the Volcanic Eifel. This former hilltop castle is an example of medieval architecture in Rhineland-Palatinate.
History+
The first documented mention of Gerolstein Castle dates back to 1115, when Gerhard von Blankenheim moved his seat of power here and had Gerhardstein Castle built, which gave the town its name. In the 13th century, under Gerhard IV, the complex underwent expansion into a stronghold with a fore- and main castle. After the extinction of the Blankenheim line in 1423, the castle passed into the possession of the von Loen family.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://de.wikipedia.org/wiki/Datei:L%C3%B6wenburg_Gerolstein_2012_Schildmauer.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: 50.2213, 6.6678