Really great hike -> I would like to recommend the Barnberg cave. She goes almost 50 m into the mountain and can be oppressive at first. My tip: take your headlamp, because after 10 m you can not see anything anymore.
Otherwise, I can recommend this hike to anyone who likes to walk longer distances. Unfortunately, I could not finish this hike because the mobile phone battery failed, but the starting point was the same as the destination point.