The remains of the Castle can be visited
Hersfeld Abbey (Ruin)

Hersfeld Abbey+
The ruins of Hersfeld Abbey in Bad Hersfeld are one of the largest Romanesque church ruins worldwide. Originally an abbey, it now serves as a backdrop for cultural events.
History+
The origins of the collegiate church lie in a hermitage founded by Sturmius in 736. Bishop Lullus of Mainz transformed it into a Benedictine monastery between 769 and 775 and had a larger church built. In 780, the remains of Saint Wigbert were transferred to Hersfeld. Abbot Bun began construction of a Carolingian basilica in 831, which was completed and consecrated in 850 under Abbot Brunwart, with Wigbert becoming the main patron. After a fire in 1038, the Romanesque reconstruction began, consecrated in 1144 in the presence of King Conrad III. The church and most of the monastery buildings were destroyed in 1761 during the Seven Years' War, when they served as a supply depot. Until the 19th century, the ruin was used as a quarry before initial preservation measures began in 1828.
Source: Wikipedia · Licence: CC BY-SA 4.0
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: 50.8666, 9.7030