The population of Diyarbakır once included many Christians, mainly Armenians and Chaldeans, but most of them were pushed out or perished during the troubles in the early 20th century or, more recently, with the Hezbollah.
The Keldani Kilisesi (Chaldean Church) , off Yenikapı Caddesi, is a plain, brightly lit church, still used by Christian families of the Syrian rite (in communion with the Roman Catholic Church). The chaplain from the Meryem Ana Kilisesi holds a service here on the second Sunday of the month. Walk past the detached minaret of the Şeyh Mutahhar Camii, take the first left (Dicle Sokak) then the first right (Şeftali Sokak). The caretaker usually sits outside the Nebi Camii.
The Armenian Surpağab Kilisesi , also just off Yenikapı Caddesi, was closed for restoration at the time of writing. It's across the lane from the Esma Ocak Evi.
The wonderful Meryem Ana Kilisesi (Church of the Virgin Mary) is still used by Orthodox Syrian Christians. The church is beautifully maintained, although only about seven families still attend services. Local kids will show you the way.
An old church near the Şeyh Mutahhar Camii is now a post office.