The upper floor of the building was used by the university to lock-up students, who were still allowed to attend lectures, who misbehaved. Nearing 1914 it became something to boast off, spending the night in the student prison. There are several rooms, and the whole is decorated with graffiti and pictures, mostly in black and in profile. Not very large, but well worth having a peak inside. This is included in the university museum ticket.