The Blue Mosque is a 17th century mosque located in Istanbul, Turkey. It was commissioned by Sultan Ahmed I and took just 7 years to build, opening in 1617. The mosque was designed to have 6 minarets, as many as the holiest site in Mecca, to demonstrate the Sultan's power. It has over 20,000 blue and white ceramic tiles and 200 stained glass windows that admit natural light. The exterior features 4 tall, slender minarets at each corner and a large forecourt surrounded by vaulted arcades.