In the US, poverty, deprivation and exploitation draws thousands of its own children down into a dark underworld that offers few ways out.
It is a world few Americans are aware of. But tens of thousands of American children are thought to be sexually exploited every year.
It's believed that every night hundreds are sold for sex.
The FBI says child sex abuse is almost at an epidemic level, despite the agency rescuing 600 children last year.
"Trafficking" often conjures images of people from other countries being smuggled over land and across the sea and then forced to work against their will in foreign lands. People are trafficked into America from Mexico, Central and South America. But the vast majority of children bought and sold for sex every night in the United States are American kids.
Source: BBC