The remains of the Castle can be visited
Derneck Castle (Ruin)

The Derneck ruin, also known as Degeneck, is a 14th-century shield wall castle on a spur near Münzdorf in the Reutlingen district. Its history is linked to the noble family of Gundelfingen.
History+
Around the year 1350, Degenhard von Gundelfingen, a member of the noble family, began the construction of Derneck Castle. In this first construction phase, the shield wall, which still characterizes the appearance today, was built, including an integrated defensive tower in the northwest. Later, the shield wall and tower were expanded into a residential stone house. After the extinction of the Gundelfingen von Derneck line in 1546, the castle changed hands several times until it was acquired by the House of Fürstenberg in 1768, which added further buildings.
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: 48.3095, 9.4965