The remains of the Castle can be visited
Falkenburg Castle (Ruin) (Berlebeck)

The Falkenburg Ruin, a former hilltop castle, was built between 1190 and 1194. It has been a ruin since the mid-15th century and is now an archaeological monument.
History+
The construction of Falkenburg was initiated by the noble lords of Lippe, Bernhard II and his son Hermann II, between 1190 and 1194. In 1405, ownership transferred to Count Simon III of Lippe. During the Everstein Feud (1403–1407), the castle served as a prison for Duke Heinrich I of Braunschweig. In the mid-15th century, a fire destroyed the complex, which consisted of a main castle and an outer bailey. Later, parts of the castle were used to expand the Gauseköte, and stones served the inhabitants of Berlebeck as building material for their house foundations. Today, the ruin is owned by Stephan zur Lippe, a direct descendant of the builders. Since 2004, the support association “Die Falkenburg e.
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: 51.8758, 8.8797