Sex Slavery

The Foundation of Brandenburg Memorials, which operates museums at the former camps, said in a statement Thursday that the forced prostitution system in the camps was a "little known phenomenon."

"The female prisoners who were forced to do sex work remained silent after 1945 about their experiences as well as about the brothel users -- male, and above all German, prisoners who were allowed by the SS to visit the brothels under a rewards system," the foundation said.

"Forced Sex Work in Nazi Concentration Camps" covers a system that ran in 10 camps between 1942 and 1945. Most of the women involved were prisoners at Ravensbrück, about 100 kilometers (60 miles) north of Berlin.

Male prisoners were allowed visits to the sex slaves to boost their productivity in the Nazi arms factories during World War II.

The foundation said that encouraging sex with women was also a means of curbing homosexuality, which the Nazis feared would "break out" among male prisoners confined to their own camps.

Trauma and shame

Women who were held at the brothels often suffered enduring psychological trauma and many did not apply for reparations after their liberation in 1945 due to the shame they felt.

Forced prostitution in concentration camps was the subject of an exhibition in Vienna in 2005.

The new exhibit at Ravensbrück, which runs until Sept. 30, incorporates filmed interviews with survivors as well as photographs and documents.

Some 132,000 women and children, 20,000 men and 1,000 adolescent girls from about 40 countries were held at Ravensbrück and the youth concentration camp Uckermark between 1939 and 1945.

An estimated 40,000 of those prisoners were killed or died of mistreatment and disease during that period.