Auschwitz I concentration camp postcard - view of the metal sign reading 'Arbeit Mach Frei' - work makes you free. Caption reads: The Gateway of the Chief Camp'.  Source: Museum of O?wi?cim, Poland. -  Photos taken by guard or SS. Publication date of postcard not known.  Konzentrationslager Auschwitz Site of murdered Jews. (Photo by Culture Club/Getty Images)