The remains of the Castle can be visited
Aardeck Castle

The late medieval hilltop castle ruin of Aardeck stands on an elevation near Holzheim in the Rhein-Lahn district.
History+
The first written mention of Aardeck Castle appears in a chronicle from 1395. It is believed that Count Adolf of Nassau-Dillenburg was the builder and that the castle originally served as a border fortification against Katzenelnbogen. From 1467, Aardeck became the main seat of the family of Dietrich von Diez, who received it as a fief from the County of Diez.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://www.wehrbauten.de/thread.php?threadid=932
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: 50.3543, 8.0415