It's hard for most of us to imagine that slavery still exists. But that is the stark message which emerges from the stories in today's Not For Sale series, a joint project by the Herald and World Vision.
The series is tackling one of world's deepest problems - the exploitation of girls through forced labour, prostitution, sex trafficking and early marriage against their will.
The broad figures indicate the scale of the problem. There are 152 million children in work around the world.
Around 15 million girls under the age of 18 are married each year - one every two seconds - and 1.2 million children are trafficked every year.