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

The Hohengundelfingen ruin, once a hilltop castle, was formerly the ancestral seat of the Gundelfingen family.
History+
The origins of Hohengundelfingen Castle date back to the 12th century, when the noble family of Gundelfingen emerged. Swigger IV von Gundelfingen, born around 1160 and living until 1228, is considered a possible builder of the castle. The preserved remains of the keep, built from bossed ashlar, date to the early 13th century, a period that coincided with the heyday of the Gundelfingen family. In 1236, the castle was first mentioned in a document. Following the division of the Gundelfingen inheritance in 1250, a gradual decline of the family began. After 1293, the castle passed into the possession of the Habsburgs and frequently changed owners in the following centuries, being pledged multiple times.
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: 48.3233, 9.5054