There are an estimated 1.4 million sex slaves in the world today; most of them are women, although there are some men and many thousands of children.
"They didn't listen. They kept bringing me clients and telling me that I had a huge debt towards them. For the fact they paid for my visa, passport and tickets."
Dorina, a former sex slave from Moldova
These women do not voluntarily enter prostitution, but have been forced under the threat of violence to have sex with men who pay their 'owners'.
Sex slavery is present in every country of the world.
In some cases, categorised as 'domestic', women are sold into brothels within their own country. But international sex trafficking of women and children is on the rise.
In this episode, Al Jazeera's Rageh Omaar investigates the enslavement and trafficking of women from Moldova, the poorest country in Europe, to wealthier European countries, in particular to the red light district of Amsterdam, one of Europe's most profitable sex markets and a major international tourist attraction.