It was organized to mark the anniversary of the city’s 1453 conquest by Ottoman Sultan Mehmed II, commonly known as Mehmed the Conqueror.
Turkish President Recep Tayyip Erdogan has repeatedly said that Hagia Sophia, a UNESCO World Heritage site which now serves as a museum, could be reconverted into a mosque.
Built in the 6th century, Hagia Sophia was the main seat of the Greek Orthodox church. It remained so until it was converted into a mosque after the Ottoman conquest of the city, then-known as Constantinople, in 1453.
Turkey’s secular founder turned the structure into a museum in 1935 that attracts millions of tourists each year.