The remains of the Castle can be visited
Château du Petit-Kœnigsbourg

The Château du Petit-Kœnigsbourg, also known as Oedenburg, is a castle ruin located in Alsace, France. Together with the nearby Haut-Kœnigsbourg, it forms a castle complex.
History+
The castle's origins date back to the 12th century, when it was likely built as a simple tower castle, possibly as an extension to the Haut-Kœnigsbourg. A document from 1174 already mentions two towers on the Staufenberg. During the Interregnum, around 1267, the Lords of Rathsamhausen expanded it. By 1398, it was mentioned as part of the Königsberg castle, but by 1417, it was already referred to as an "öden burg" (deserted castle), indicating its abandoned state at the time.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://commons.wikimedia.org/wiki/File:Oedenbourg_02.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: 48.2493, 7.3392