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

The Honburg ruin, originally a fortress, was one of the most important Württemberg state fortresses in the late Middle Ages.
History+
The Honburg fortress was built in 1460 under Count Eberhard im Bart. During the Thirty Years' War, in 1645, the complex was destroyed down to its foundations. This was reportedly done on the orders of Konrad Widerholt, commander of Hohentwiel Fortress, by its own garrison to protect Tuttlingen from enemy troops. However, there are also views that the walls had already fallen into disrepair by 1643, at the time of the Battle of Tuttlingen. Later, the stones of the ruin were used as building material, including for the Swabian Ironworks Ludwigstal and, after the city fire of 1803, for the reconstruction of Tuttlingen. It was not until the 19th century that the two towers of the complex were rebuilt through donations, though not in their original form.
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: 47.9797, 8.8233