The Dutch windmill, both the southwest corner and defensive tower of the medieval city fortifications, was built around 1390. It has seven floors with a revolving hood and gallery, as well as a sack elevator. The entire wheel and wooden structure is approximately 300 years old. The windmill's wings are now rotated by an electric motor (display installation). The ground floor houses a medieval former dungeon and later sack storage facility, as well as a small museum.