Hagia Sophia, officially the Hagia Sophia Grand Mosque, is a mosque and a major cultural and historical site in Istanbul, Turkey. It was formerly a church (360–1453) and a museum (1935–2020). The last of three church buildings to be successively erected on the site by the Eastern Roman Empire, it was completed in AD 537, becoming the world's largest interior space and among the first to employ a fully pendentive dome. It is considered the epitome of Byzantine architecture and is said to have "changed the history of architecture". From its dedication in 360 until 1453, Hagia Sophia served as the cathedral of Constantinople in the Byzantine liturgical tradition, except for the period 1204–1261 when the Latin Crusaders installed their own hierarchy. After the fall of Constantinople in 1453, it served as a mosque, having its minarets added soon after. The site became a museum in 1935, and was redesignated as a mosque in 2020.
Insider tip — The northern Bosphorus shore around Sarıyer and Beykoz is a world of summer palaces, Belgrade Forest, and the village of Anadolu Kavağı at the Black Sea entrance to the straits — where Byzantine, Genoese, and Ottoman fortifications guard the approach to Istanbul from the Pontic north. The Baths of Avcı Mehmet (Hunter Mehmet) served the historic Bosphorus villages where Ottoman sultans kept hunting lodges and summer retreats in the forests above the city during the centuries when Istanbul was the capital of the world's most powerful empire.
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