At its lower levels the interior of the Sultan Ahmed Mosque (Sultan Ahmet Camii) is lined with more than 20,000 handmade ceramic tiles, made at Iznik (the ancient Nicaea). Its upper levels are painted. More than 200 stained glass windows with intricate designs admit natural light, today assisted by chandeliers. The decorations include verses from the Holy Koran, many of them made by Seyyid Kasim Gubari, regarded as the greatest calligrapher of his time.
