The remains of the Castle can be visited
Oberbolheim Castle

The castle ruin of Oberbolheim, also known as Alte Burg or Versunkene Burg, is a lowland castle. It is situated in a forested area near Nörvenich in the Düren district.
History+
The complex, a large motte, was inhabited in the 13th century, with Hermann IV von Saffenberg mentioned as the lord of the castle. The main castle was built of stone and measured approximately 60 by 35 meters. A horseshoe-shaped outer bailey, located in front, was separated from the main castle by a wide and deep moat.
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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: 50.8141, 6.6467