The original name of mosque is Sultan Ahmet Mosque and it is still an active mosque. But it is known as Blue Mosque because of tiles and inner decoration. They used 21,000 tiles for inner decoration. The mosque has 260 windows and 6 minarets. It was constructed by Sedefkar Mehmed Aga between 1609-1616 during the Ottoman Sultan Ahmet I. There is a tomb of founder, a madrasah and a hospice near the mosque as well.