Oflag IV-C

Oflag IV-C, often referred to by its location at Colditz Castle, overlooking Colditz, Saxony, was one of the most noted German Army prisoner-of-war camps for captured enemy officers during World War II; Oflag is a shortening of Offizierslager, meaning "officers' camp".

This thousand-year-old fortress was in the heart of Hitler's Reich, four hundred miles from any frontier not under Nazi control. Its outer walls were seven feet thick and the cliff on which it was built had a sheer drop of two hundred and fifty feet to the River Mulde below.

Source: Wikipedia