The remains of the Castle can be visited
Untere Sachsenburg Castle

The Lower Sachsenburg castle ruin, also known as Unterburg or Hakenburg, is a ruin of a hilltop castle in Thuringia. It is above Oldisleben-Sachsenburg.
History+
The exact construction period of the Lower Sachsenburg is not definitively known. Possible builders could have been the Counts of Orlamünde, who held dominion until the mid-11th century, or the Landgraves of Thuringia, who owned the castle by 1180 at the latest. Its strategic importance lay in securing access to the central Thuringian Basin. After the death of Heinrich Raspe in 1247, Count Siegfried of Anhalt occupied the Palatinate of Saxony and presumably the castle. He had the Upper Sachsenburg built for reinforcement. Although the Treaty of Weißenfels in 1249 stipulated the demolition of the castle, it is doubtful whether this actually occurred, as it was successfully defended against Adolf of Nassau in 1287.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: https://commons.wikimedia.org/wiki/File:Untere_Sachsenburg_01.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: 51.2935, 11.1653