The remains of the Castle can be visited
Kasselburg Castle

The Kasselburg castle ruin, a complex on a basalt outcrop in the Vulkaneifel, has a 37-meter-high gate and residential tower, designed as a double tower.
History+
The origins of Kasselburg date back to the 12th century, though the exact builders are not fully confirmed, possibly the Lords of Castel. The complex was first documented in 1291. After 1335, the castle came into the possession of Gerhard V von Blankenheim, who founded the Blankenheim-Kasselburg line. In the 14th century, the palas and the keep were built, the latter later expanded into a residential tower. From 1452, the castle underwent expansion, particularly the outer bailey with its economic buildings. After the extinction of the Blankenheim-Kasselburg line in 1406, the castle changed hands multiple times through marriage and inheritance, including the Counts of der Mark and the Dukes of Arenberg. In the 17th century, ownership disputes arose, which were settled in 1674 by the Imperial Chamber Court.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://www.wehrbauten.de/thread.php?threadid=2041
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: 50.2392, 6.6853