The Fortification can be visited
Hohenwerfen Fortress

Hohenwerfen Fortress, a medieval complex, is situated on a rock cone in the Salzach Valley in Austria. Its strategic location between the Tennen, Hagen Mountains, and Hochkönig makes it a landmark of the Salzburg region.
History+
The construction of Hohenwerfen Fortress was initiated between 1075 and 1078 by Archbishop Gebhard of Salzburg. Originally built in a simple style, as masonry castle construction was still in its early stages, the complex was later reinforced with embrasures, defensive oriels, and flanking towers. An initial completed castle complex emerged between 1127 and 1142. In 1525, during the Peasants' War, the fortress suffered fire damage, followed by extensive renovations that included a barred arch building, a bastion with the Wallerturm, as well as a covered passage and the Finsterer Stiege.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://commons.wikimedia.org/wiki/File:Festung_Hohenwerfen.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: 47.4827, 13.1882