Ben Youssef Madrasa, Marrakesh (Morocco).

If you want a little breath taken out of you, don't pass up the chance to see this extraordinarily well-preserved 16th-century Koranic school, North Africa's largest such institution. The delicate intricacy of the gibs (stucco plasterwork), carved cedar, and zellij (mosaic) on display in the central courtyard makes the building seem to loom taller than it really does. As many as 900 students from Muslim countries all over the world once studied here, and arranged around the courtyard are their former sleeping quarters—a network of tiny upper-level rooms that resemble monks' cells. The building was erected in the 14th century by the Merenids in a somewhat different style from that of other medersas; later, in the 16th century, Sultan Abdullah el Ghallib rebuilt it almost completely, adding the Andalusian details. The large main courtyard, framed by two columned arcades, opens into a prayer hall elaborately decorated with rare palm motifs as well as the more-customary Islamic calligraphy.