The mosque, called Sultanahmet Camii by Turks, was commissioned by Sultan Ahmet I in 1609-1617 to be built next to the Hagia Sophia mosque. Built by Sedefkar Mehmet Aga, famous architect Mimar Sinan’s student, the mosque has a central dome with a height of 43 meters (141 feet) and 23.5 m (77 ft) in diameter. The Sultanahmet Mosque is called the Blue Mosque by foreign tourists because of its tiles. The Blue Mosque was inscribed on the UNESCO World Heritage Site list in 1985. ECI reports, citing Anadolu Agency.