One of the most famous historical sites in Dienstein is the castle where Charles I, the Lionheart King of England, was defeated and imprisoned. Due to disrepair, only a few ruined walls remain. This is also the commanding height of Dienstein and you can overlook it. A big 90-degree turn of the Danube at the foot of the mountain. It takes about half an hour to climb the trail to the top of the mountain. Don’t believe the estimated time on Google Maps.