The remains of the Castle can be visited
Nanstein Castle

On a foothill near Landstuhl, in Rhineland-Palatinate, stands the Nanstein Castle Ruin. Originally built in the 12th century, it later gained fame through its owner Franz von Sickingen, a rebellious knight. The complex is partially integrated into a red sandstone rock, which also bears the name Nanstein.
History+
Around 1160, Nanstein Castle was built under Emperor Barbarossa as part of the Staufer fortification system in the Palatinate and served as the seat of an imperial ministerialis. Inheritances led to uncoordinated expansions, which impaired its defensive capabilities. In 1482, Knight Schweickhardt von Sickingen became a co-owner; his son Franz von Sickingen acquired the castle completely by 1518. Franz attempted to convert Nanstein into a cannon castle, but these efforts proved futile in 1523 when the castle fell after only two days of bombardment by a princely army, and Franz von Sickingen died from his injuries.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://www.wehrbauten.de/thread.php?threadid=1326
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: 49.4098, 7.5729