The Castle can be visited
Museum
Frankenhausen Castle

In Bad Frankenhausen in the Kyffhäuser district, Thuringia, stands Frankenhausen Castle, a former secondary residence of the House of Schwarzburg-Rudolstadt. This castle, which dates back to a medieval fortress, is now a museum.
History+
The origins of Frankenhausen Castle lie in a medieval fortress at the water gate of the town's fortifications. At the end of the 14th century, the complex came into the possession of the Counts of Schwarzburg, who expanded it into a fortress to assert themselves against neighboring rulers. In addition to its role as a residence, the castle also served the administration of Frankenhausen and its saltworks. During the Peasants' War in the 16th century, the castle suffered damage and was subsequently rebuilt in the Renaissance style between 1533 and 1536. A town fire in 1689 also affected the castle, with only the east facade retaining its original Renaissance appearance.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: Roland Neubert, Halle (Saale)
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: 51.3539, 11.1019