To be privately owned
Gangelt Castle (Ruin)

The ruins of Gangelt are in the historic municipality of Gangelt in the district of Heinsberg, North Rhine-Westphalia. Of the former castle complex, only a residential tower remains today, continuing to shape the landscape as private property.
History+
The origins of Gangelt Castle date back to the 14th century, with its first documented mention around 1365. It was linked to Gangelt's town fortifications, built around 1250, which after 1400 included a town wall with three gates; two of these, the Bruchtor and the Heinsberger Tor, are still preserved today.
Source: Wikipedia · Licence: CC BY-SA 4.0
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: 50.9920, 5.9984