Aya Sofya, built by Emperor Justinian, is a former Orthodox patriarchal basilica, later a mosque, and now a museum in Istanbul, and right outside my window on the Europe side of the Bosphorus. From the date of its dedication in 360 A.D. until 1453, it served as the cathedral of Constantinople, except between 1204 and 1261, when it was converted to a Roman Catholic cathedral. The building was a mosque from 1453 until 1931, when it was secularized. It was opened as a museum in 1935. I am walking up there in a few moments.
I may well take a day off of blogging.