Hagia Sophia (Ayasofya in Turkish) is a former Greek Orthodox Christian patriarchal cathedral, later an Ottoman imperial mosque and now a museum in Istanbul. Built in AD 537, it was famous in particular for its massive dome. It was the world's largest building and an engineering marvel of its time. It is considered the epitome of Byzantine architecture and is said to have "changed the history of architecture."

Now Turkey's authoritarian leader, Recep Tayyip Erdoğan, wants to turn it back into a mosque.

Best to view in "Original" because other versions resized by Pbase are decidedly unsharp.

Old Executive Office Building, posted earlier: