The remains of the Castle can be visited.
Keula Castle (Ruin)

The Keula Ruin, once a moated castle, is located in the Kyffhäuser district in Thuringia.
History+
The origins of the Keula moated castle date back to 967, when it was first mentioned as an Ottonian royal estate. The castle changed hands several times and served, among other things, as the official seat of the Honsteiners before passing into the possession of the Schwarzburgers. In the 17th century, the complex underwent various expansions, but in 1772 and 1811, parts of the castle were demolished, leading to its current ruined state.
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: 51.3317, 10.5272