Down a lane to the north of place Ben Youssef is the entrance to the 16th-century Ben Youssef Medersa, a former Koranic boarding school attached to its namesake mosque, where students used to learn Islamic law, science, and the Koran. A stunning example of the Saâdian dynasty's attention to detail and craftsmanship, this is one of Marrakech's most important Islamic monuments. A peaceful and meditative place when not invaded by large tour groups (come around lunchtime or at the end of the day), the Medersa is centered around an unusually large square courtyard containing a rectangular pool and wide, columned arcades on two sides. Above them are the dormitory quarters where up to 800 students were crammed into cell-like rooms. Note the well-weathered cedar-wood carving on the upper facades of the main courtyard as well as the exquisite zellij and stucco on the arcades' floors, walls, and pillars. At the far end of the courtyard you'll see the wood dome of the prayer hall, where the interior is best preserved, especially the zellij. Set in the wall and, as always, in the direction of Mecca is a five-sided mihrab, or prayer niche, decorated with pine cone and palm motifs and Arabic inscriptions.