There are at least 8.4 million child slaves in the world today. Nearly two million of these are forced to work as prostitutes, while almost half a million are child soldiers.
"It's like living in a family, but you're not a part of the family. It's like living in a home that's not your home, because eventually you know they're going to tell you to get out. It's living in fear - fear of the adult and fear of the unknown."
Jean-Robert Cadet, a former restavek
But the largest proportion of child slaves - more than five million - are held as forced labour.
In some countries, these child slaves are simply juvenile victims of a thriving adult slave culture, but in other countries children are bought and sold specifically as child labourers.
In this episode of Slavery: A 21st Century Evil, Rageh Omaar investigates the plight of child slaves in Haiti.
They are known as 'restaveks' from the French words 'rester avec', meaning 'to stay with'. This is the practice of poor families giving their children as domestic help to wealthier acquaintances or relatives.
As well as taking place within Haiti, this form of slavery can also involve children being sold or trafficked to the US.
Our investigation exposes the slave traders who lure these children from isolated villages and then sell them to wealthy families.