Around a Byzantirte church one km. to the west of Derinkuyu there exist hundreds of rooms. The secret tunnel which joins these rooms with Manast?r at Derinkuyu was open as recently as 1945, after which date the roof fell in in many parts and blocked the way; all the same it is a very interesting place.
Those parts which can still be visited have only one storey; the twelve columns hewn out of the rock represent the twelve saints. The blocked passageways have unfortunately prevented us from making an accurate assessment of the area covered by this underground settlement; nor do we know on how many levels it was built. The ventilation ducts of this under¬ground city in some cases have been blocked by the villagers living in the neighbourhood or natural causes, such as rain, snow and wind have deposited earth and rocks in them, rendering them useless.
Owing to natural causes again the tunnel is blocked; in the part where one can walk one can see rooms on both sides. The Greeks who used to live at Derinkuyu called this place the church of the Twelve Saints. The world for Saint in Greek is Aghia, hence the present name given to the place: Ayan. The structural characteristics of Ayan closely resemble those of the underground city of Özkonak, which, alongside with Derinkuyu and Kaymakl?, is one of the three underground cities open to visitors among more than thirty such places in this region.