Taking off his shoes as tradition requires, Obama stepped into the 17th-century Sultanahmet Mosque in the ancient heart of Istanbul, accompanied by Turkish Prime Minister Recep Tayyip Erdogan amid tight security in the area.

Two Muslim preachers guided Obama inside the grandiose edifice — better known as the Blue Mosque for its blue tileworks — and the president smiled when they showed him a dome scripture mentioning the Prophet Mohammed's grandson Hussein, Obama's middle name, Anatolia news agency reported.

at some point before President Obama's speech in historic Gaston Hall on the campus of Georgetown, someone appears to have covered in black cloth the letters "IHS" and cross that are displayed directly above the speaker's head at the center of the stage