Last week I attended Fener-Balat region tour with Istanbul Travel Club. As far as I understand this region was the old Istanbul and mainly where the non-muslim folk of the Ottoman Empire lived. It is full of historical places, mostly churches.
And don't forget the Vatican of the Orthodox community, the Fener Greek Patriarche.
The Greek High School near the Patriarche.
Also nearly Pieere Loti's Cafe has a great view although it is hard to climb there:)
In brief,I can say that the region is really lovely and historic.