Hagia Sophia is one of the most famous structures in Istanbul. It was built by the Byzantine Emperor Justinian I as a patriarchal cathedral between 532 and 537.
After the Ottomans took the city in 1453, Mehmet the Conqueror converted Hagia Sophia into a mosque. Today, it is open to the public as a mosque with its magnificent architecture. Hagia Sofia’s length is 82 meters and width is 73 meters. There is no entrance fee.