Steinerner Turm Hardheim

The square tower, built of quarry sandstone, about 30 meters high with a side length of 6.4 meters and a wall thickness of 2.1 meters in the lower area is located east of today's B27 (Walldürner Straße) and is bordered by Holzgasse and Riedstraße.
de.wikipedia.org/wiki/Untere_Burg_Hardheim#Beschreibung

The stone tower is the only remnant of the former Lower Castle, which was partially destroyed in the 15th century and then collapsed. The tower is believed to have been built around the year 1200.The tower is 30 m high and can be climbed via an internal wooden staircase with 127 steps.
However, the tower is closed during the kestrel breeding season, but outside the breeding season it is accessible by appointment.
(However, we were told during the tour that it is only open once a year🤷)

Lower Hardheim Castle was a lowland castle from the High Middle Ages on the southern edge of the town center of Hardheim. Its remnant, the Stone Tower, the former keep, is now a local cultural monument.