Hagia Sophia

A cathedral, a mosque, a museum, and a mosque again/Ancient Structures

Hagia Sophia in Istanbul was the largest cathedral in the world for nearly a thousand years after its completion in 537 AD. Its central dome rises 55.6 meters above the floor and spans 31 meters. The building has survived earthquakes, sieges, and multiple religious conversions. Its architects, Isidore of Miletus and Anthemius of Tralles, were mathematicians, not architects.