The remains of the Castle can be visited
Old-Wartburg Castle

The Alt-Wartburg castle ruin is in Switzerland, situated on a secondary peak of the Engelberg mountain range. It overlooks the Aare and Wigger valleys.
History+
The construction of Alt-Wartburg took place shortly before the year 1200 by the Lords of Ifenthal. Werner von Ifenthal appears in documents from 1201. During the 13th century, the castle underwent expansion, which was completed around 1325. In the mid-14th century, the castle passed into the possession of the Lords of Büttikon, who sold it to the Hallwyler family in 1379.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://commons.wikimedia.org/wiki/File:AltWartburg02.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: 47.3333, 7.9190