The remains of the Castle can be visited
Lichtenfels Castle

Lichtenfels Castle Ruin, once a hilltop castle, is on a peninsula of the Ottenstein reservoir in the Waldviertel, Lower Austria. It is in the municipality of Zwettl-Friedersbach.
History+
The origins of Lichtenfels Castle date back to the 12th century, when German kings granted the Kamp region to minor noble families for cultivation. Around 1136, Hartung von Rauheneck received this fief from Duke Heinrich Jasomirgott and built the castle in the mid-12th century. The Rauheneck family, also known as the Tursen, held the fief until 1335 before it reverted to the duke. Hugo der Turs von Rauheneck was mentioned in 1248 in Austria's first German-language document. Later feudal lords included the Lords of Kapell. During the Hussite Wars around 1427/28, the castle served as a haven for the treasures and library of Zwettl Abbey.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://commons.wikimedia.org/wiki/File:Burgruine_Lichtenfels.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: 48.5903, 15.3234