Here in the forest northwest of Franzdorf lie the remains of a medieval castle. However, only the remains of the ramparts and ditches remain, as well as some debris from fieldstone walls or foundations. The complex has a diameter of around 40m and stands out clearly from the otherwise flat landscape. Interestingly, the castle ruins lie exactly on the district border, i.e. on the border of the former duchies of Holstein and Lauenburg. The castle also gives its name to the municipality of Steinburg, which was created in 1978 from the merger of Eichede, Mollhagen and Sprenge. Coming from the direction of Mollhagen or Sprenge, the forest path appears to end here. For experienced mountain bikers, however, it should not be a problem to overcome the ramparts and ditches and continue the path on the other side towards Franzdorf.