Blue mosque is famous with its exquisite tiles decorated in its interior and well-known in both Turkish and Islamic worlds. It was built by Sultan Ahmet I in the early 17th century, and designed by a pupil of Sinan, the greatest of Ottoman architects. It is the only imperial mosque with 6 minarets and 260 windows illuminating its grand chamber, which is decorated with more than 20, 000 Iznik tiles.