When I saw this lecture of Prof. dr. D. Frenkel trough fabchannel (very easy to follow) I thought about these pictures I took in 1993. We all know the flowers on our window but these were massive.It was in an old stone mine. A gap of approx. 40 meters deep and 400 by a 200 meters wide.
I went back there (near Winterswijk) 3 times before I could let go.0