Urbex : Fort La Chartreuse (Belgium)

This place is Fort La Chartreuse in Belgium. (near Luik).
It is a fort that was build by the Dutch in 1817 for the defense of Luik and it became property of the Belgians after the Belgium Revolution in 1830. It has been used as a prison by the Germans during WW1 and WW2.

The fort is abandoned since 1980.

This location is well-known in the Urbex community. This was the second site that I've visited (with @guchtere ).
I could only find the JPG files (don't know if I even had RAW files of them) of which I've selected a few and edited them into a Black&White series.