Well, in limestone mountains you can find stone windows quite often. But they are allways beautiful. Thanks for posting this nice picture!
I'm glad you like it. I have only come across one stone-window except this one, and that was in the Fagaras mountains (Southern Carpathians, Romania).
Come once in Slovenia. In Julian Alps there are many. Especially known are both stone windows of Prisojnik.
I have come across quite a lot of windows myself - and not only in limestone. The most famous one is Capu Tafunatu in Corsica, made of red granite!