The Wikipedia has: “The Hagia Sophia (Greek: Ἁγία Σοφία, "Holy Wisdom") at Nicaea is a Byzantine-era church in Nicaea (now known as İznik) in Turkey. The church of Hagia Sophia was built by Justinian I in the middle of the city in the 6th century. It was in this building that the Second Council of Nicaea met in 787 to end the first period of Byzantine Iconoclasm. A timber-roofed basilica with a central nave and side aisles, it was built shortly after 1065, but extensively remodelled after its conversion into a mosque. Before the remodelling it had two rows of triple arcades on columns that carried a clearstory wall with five windows. It was converted to a mosque after the fall of the city to the Ottoman Turks in 1337, and functioned as such until it was converted into a museum in 1935. In November 2011 it was again converted into a mosque. “
A notice at the entrance mentions destruction in 1920 by the Greeks, an omission in the Wikipedia text. I do not know what happened next, when I first saw the building it could be visited, but lacked a roof. It has since been restored and functions as a mosque (now called the "Aysofya Camii (Orhan Camii)" on one sign at the entrance, though above that entrance in etched glass its name is "Ayasofya Orhan Camii") that can also be visited for the building itself. An Italian researcher asked me to look for traces of frescos and other ornaments. I was about the only visitor who noticed a Christ figure, with some surrounding figures, almost at floor level, and some traces of ornaments. To my horror I saw I missed a few saints or angels (I suppose, because of their halo) in one of the towers, that I only saw when back home. Sorry for not taking their close-up picture.
In this gallery I first show the 2018 situation, and then some older pictures.