This is the Burmalı Minare Camii (Spiral Minaret Mosque), built between 1237-1247 by the Selcuks.

On the picture: The prayer hall (21½ m x 14½ m). Six pillars carry the weight of three little domes (having 5 m diameter each).

Correspondent: J.M.Criel, Antwerpen.
Sources: ‘Vakıf Abideler ve eski Eserler’ - Vakıflar Genel Müdürlüğü, Ankara 1983.