In the summer of 1943, SS chief Heinrich Himmler ordered that "special buildings" (brothels) be established at each men's concentration camp, to corrupt political prisoners and to provide "recreation" for SS guards and camp administrators. Each received 18 to 24 women prisoners from Ravensbrück, who were promised release after six months of sex slavery.

Below: This November 9, 1944, parcel card from the administration of women's concentration camp Ravensbrück to woman prisoner Wanda Kasmikowska at men's concentration camp Buchenwald is the only recorded example of sex-slave mail.

Official mail, postage free, not delivered (no explanatory endorsement.)