Fairy chimneys in Monks Valley. Monks Valley is located in Cappadocia, which is a touristic term for the central part of Turkey. Fairy chimneys have a thin layer of hard volcanic rock on top of a thicker layer of tuff, which is soft and easily eroded. The chimneys form when the softer rock is eroded away faster than the hard rock, until eventually the hard bit at the top of the “chimney” falls off.