Hagia Sophia (Ayasofya-i Kebir Cami-i Şerifi)

Hagia Sophia's history spans nearly 1,500 years and three religious identities, beginning with Emperor Justinian I's decision to rebuild the church destroyed in the Nika riots of 532 AD; the new cathedral, designed by Isidore of Miletus and Anthemius of Tralles, was consecrated in 537 AD after a construction campaign of under six years, an extraordinary pace for a building of its scale. For nearly a thousand years it stood as the largest enclosed space and the largest cathedral in the Christian world, and its innovative system of pendentives allowed the 55-meter-high, 31-meter-wide dome to appear to rest weightlessly atop a ring of forty windows. The interior preserves extensive Byzantine mosaics, including the Deesis mosaic of Christ Pantocrator flanked by the Virgin Mary and John the Baptist in the upper gallery, the Empress Zoe mosaic, and the apse mosaic of the Virgin and Child, most executed in the 9th to 13th centuries after the earlier iconoclast period. Following the Ottoman conquest of Constantinople in 1453, Mehmed II converted the building into an imperial mosque, adding a mihrab, minbar, and eventually four minarets, while later sultans commissioned the eight giant black-and-gold calligraphic roundels bearing the names of Allah, Muhammad, and the early caliphs that still ring the nave. Mustafa Kemal Ataturk secularized the building as a museum in 1934, prompting a long restoration program that uncovered many of the plastered-over mosaics, before a 2020 Council of State ruling returned it to active mosque status. The building today is presented as a working mosque with carpeted prayer areas on the ground floor, while the historic mosaics in the galleries and upper sections remain visible, curated less as a museum collection and more as a layered monument where Byzantine and Ottoman elements are read side by side in situ. Structural restoration is ongoing and near-continuous, focused on the dome's buttressing system and the stabilization of masonry repeatedly damaged by earthquakes over the centuries, most seriously in 989 and 1346.