The remains of the Castle can be visited
Falkenstein Castle
The castle ruin of Falkenstein, once a hilltop castle, is on a rocky outcrop near Breitnau in the Breisgau-Hochschwarzwald district. It protected the trade routes of the Höllental valley.
History+
The construction of Falkenstein Castle is presumed to have occurred around 1200, initiated by a ministerial family of the Zähringer dynasty. The Lords of Falkenstein, first documented between 1137 and 1148, rose to become a noble family in the Breisgau. They controlled the trade route through the valley, which connected the Breisgau with the Baar region and Lake Constance, extending their sphere of influence as far as Hinterzarten and Titisee. The castle served to protect this route and secured toll revenues for the Falkensteins.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://commons.wikimedia.org/wiki/File:02,_Falkenstein_-_H%C3%B6llental.JPG
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: 47.9407, 8.0168