Walim
In Walim (german Wüstewaldersdorf), southwestern Poland, a satellite camp subordinated to Gross-Rosen was set up in 1943. Camp prisoners were used as slave labor for large tunnel constructions (anlage Riese) in the area. The camp itself was located within an existing factory area.
Current status: Demolished (2013).
Location: 50°41'50.09" N 16°26'42.06" E
Get there: Car.
Follow up in books: Kogon, Eugen: The Theory and Practice of Hell: The German Concentration Camps and the System Behind Them (2006).
The ruins are still there and off limit, but the fences that exist are ignored. However, it is important to be vigilant when entering the ruins. Cracks and absence of guardrails can be fraught with danger if you stumble or take a wrong step.