of the church of constantinople. >> simon: and in the beginning, istanbul was called constantinople--osphorus where east meets west. the city's skyline is dominated by minarets. at friday prayers, the mosques are teeming. ( bell rings ) but the city's richest and most renowned christian churches are museums today, mecca's for tourists, not for worshipers. from the chora church, with its fresco of jesus whose eyes seem to go right through you, to the hagia sophia, the first great church in christendom and an architectural wonder built a thousand years before st. peters in rome, and for centuries, the most important church in the christian world. ( chanting ) fast forward a few centuries and it's hard to find christians in istanbul. this church holds 500 people, but during its sunday service its pews were practically empty. it was the same everywhere we went. at the turn of the last century there were nearly two million orthodox christians in turkey. one and a half million were expelled in 1923 and another 150,000 left after violent anti- christian riots in istanbul in 1955. today, in a