Hagia Sophia
Look down into a nave that was the largest enclosed space on earth for nearly a thousand years — and is a working mosque once more.
Enough context, no spoilers
Why it matters
Justinian I commissioned it after the Nika riots destroyed its predecessor in 532, and Isidore of Miletus and Anthemius of Tralles raised it in five years. An earthquake brought the dome down in 558; it was rebuilt higher by 562. It served as the cathedral of Constantinople for nine centuries, became a mosque under Mehmed II in 1453, was secularised as a museum in 1935, and was reconverted to a mosque in July 2020.
What to know before you go
Since January 2024 foreign visitors have entered by a dedicated tourist gate and follow a one-way route through the upper galleries only; the ground-floor nave is reserved for worshippers. Budget an hour and go at opening, before the tour groups arrive from the tram stop. Since April 2025 the largest restoration in the building's history has been under way on the domes and minarets, with a 43.5-metre scaffolding tower standing inside the nave and a crane on the eastern façade — the mosaics stay visible, but the open sweep of the interior does not. The Blue Mosque, the Hippodrome and the Basilica Cistern are all within five minutes on foot, so this is the natural first stop of a Sultanahmet day.