Zinciriye Medresesi, (on the hill towards the citadel; look for the sign on the main street). A madrasah (Islamic school) built by the Artuqids, rulers of the area then, in 1385. Rooms surrounding the central courtyard have some beautiful wall and ceiling decorations, having similarities with Seljuq art of central Turkey. Definitely a must-see while in Mardin. Free.
