Non-Muslims cannot visit the green-roofed mausoleum but the remarkable library inside the adjacent Quranic school is open to all – providing the keyholder's around. Among the 4000 ancient manuscripts that remain on the glassed-in shelves – there used to be around 50,000, now lost or in other museums – are maps with precise details, exquisite calligraphy and a Quran written on gazelle hide dating back to 11th-century Cordoba. Find it through an arch in the northwest corner of the main square. No photographs.