The remains of the Castle can be visited
Sprengelburg Castle

The Sprengelburg castle ruin, also known as Springeburg, is a hilltop castle in the district of Kusel in Rhineland-Palatinate. It sits on an offshoot of the Königsberg between Eßweiler and Oberweiler im Tal, directly on state road 372, and has been protected as a monument since 1983.
History+
The Sprengelburg was probably built in the 13th century at a strategically important point: the narrowest part of the Talbach valley. Its purpose was to control the road that ran through the valley floor at that time. The Knights of Mülenstein are recorded as the lords of the castle, serving as vassals of the Rheingraves in Grumbach. Whether they were also the builders is not certain. The Mülenstein family is documented between 1317 and 1451. They were known as robber knights and caused considerable damage to merchants on the road. In retaliation, the castle was destroyed by Strasbourg merchants. The exact date of destruction is unknown, but a report from 1595 points to the solar eclipse of 1441 as a possible time, as after unsuccessful clearing attempts by farmers, the castle grounds were completely overgrown.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://www.wehrbauten.de/thread.php?threadid=1347
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: 49.5663, 7.5578