The Phanar Greek Orthodox College is the great red-brick landmark that dominates the skyline above Fener and Balat, visible from across the Golden Horn. Often called the "Red Castle," the huge domed building was completed in 1881 in a monumental style sometimes likened to a fortress or a Byzantine palace, designed by the Ottoman-Greek architect Konstantinos Dimadis.
It is the oldest surviving Greek Orthodox school in Istanbul, founded in 1454 — the year after the conquest — though today only a handful of students attend, reflecting the dwindling of the city's once-large Greek community. The building is generally not open to casual visitors, but it is one of the area's defining sights, and the climb up the steep streets toward it gives a good sense of old Fener. Photograph it from the waterfront for the full effect.