The Blue Mosque or Sultanahmet Camii is a historic mosque of Istanbul, known as the Blue Mosque because of ceramic adorning the walls of its interior. It was built between 1609 and 1616, during the reign of Sultan Ahmet 1 who decide to build it to appease God after the unfavorable outcome of the war with Persia. It has the tomb of the founder, a school and a hospice. It is the starting point for caravans of Muslim pilgrims to Mecca, it has six minarets. Its dome 23.5 meters in diameter is supported by four massive pillars and buttressed by four semi-domes; 260 windows flood the light building. The interior is decorated with 21,043 tiles from Iznik in a dominant blue. The prayer hall is topped by an ascending system of domes and semi-domes, each supported by three porticos, culminating with the large central dome which has 43m high at its central point. The decorations include verses from the Koran. The floors are carpeted, with carpets given by the faithful and are regularly replaced when worn. The most important element in the interior is the mihrab made of marble. The yard is about as large as the mosque itself and is surrounded by a continuous, rather monotonous vaulted arcades. The central hexagonal fountain is rather small in contrast to the dimensions of the court. The monumental door, but wide, to the courtyard is characterized by the architecture of the arcade. Until recently the muezzin calling to prayer or had to climb a narrow spiral staircase five times a day to announce the call to prayer. Today a public sound system is used, and the call can be heard through the old part of the city, echoed by other mosques nearby.
The Sultanahmet Mosque has become one of the most popular tourist attractions of Istanbul. Large crowds of Turks and tourists gather at sunset in the park in front of the mosque to hear the call to evening prayer at sunset and the mosque is brilliantly illuminated by colored spotlights.
The large backyard has sanitary facilities on both sides.