With a capacity for 20,000 worshippers, a library packed with precious manuscripts, and a student body from across the Islamic world, the Kairaouine Mosque and university is a must-see on any tour of the Medina of Fez. As with all Moroccan mosques, however, only Muslims are allowed to pass through the doors and admire its austere white archways, delicate woodwork, and elegant but restrained calligraphy. While a stop at the Kairaouine Mosque is common on Fez medina walking tours, non-Muslims should look for a tour that includes a rooftop visit to soak up the view.