I asked the train of children that inevitably followed me during my explorations. They explained that it was now blocked, but that it originally led to Ayasofya. During subsequent research on the Kariye, I actually found an historical reference to it. In 1578, the German embassary Stephan Gerlach found Jews spinning, winding, and preparing silk in a dry cistern by the entrance to the former Chora monastery. About the same time that I found the reference, the last visible remnant of the cistern vanished with the widening of the street.
Legends die harder than do crumbling remains.
So I was told at the Balikli Kilise and at several other churches. Tales of such tunnels also appear in Ottoman writings of the of the early nineteenth century, if not earlier. Some tales are more embellished than others. Dwight once recorded a peculiar incident that occurred in 1872 while American missionaries were digging new foundations for their headquarters. They chanced upon a variety of antiquities, including burials from the Roman and early Byzantine periods, architectural fragments, and a statue.