The Mosque of Saint Sophia [La Mosquee Ste. Sophie]
Originally a Byzantine Church from the 6th century CE, the Haga Sophia was the largest cathedral in the world for ten centuries - longer than any similar structure since. After the Ottoman conquest of Constantinople it was converted into a mosque and now is a museum. The four minarets were added by the Ottomans when it became a mosque. Today its Christian artwork and frescoes are slowly being recovered by archaeologists. It is one of the most visited tourist sites in modern Istanbul.