India, July 13 -- The Blue Mosque undoubtedly has its place in Istanbul but it is the Hagia Sophia which has the heart of every visitor. For rarely does one find such a secular icon in any world culture. Built as a cathedral, it has lasted since the 6th century through waves of conquests in Turkey , each era adding a layer of syncretism and a defining mark but never swamping its preceding legacy. So even though it was converted into a mosque after the Ottoman conquest in 1453, with domes on the outside, its insides were not defaced but just covered with lime wash and concealed. Just the practice of faith and its prayers changed. So Christian emblems, including the famous mosaic of the Virgin Mary on its central dome, were preserved throug...