Visitors walk at an exhibition inside the Byzantine-era Hagia Sophia, in the historic Sultanahmet district of Istanbul, Friday, Oct. 15, 2010. Turkish President Recep Tayyip Erdogan is scheduled to join hundreds of worshipers Friday, July 24, 2020, for the first Muslim prayers at the Hagia Sophia in 86 years, weeks after a controversial high court ruling paved the way for the landmark monument to be turned back into a mosque. (AP Photo/Emrah Gurel)