It is a nation built on the abolition of slavery, but there are at least 40,000 slaves in the US today. Many of them are trapped in food chain slavery, which is considered one of the easiest forms of slavery to stamp out. Why then is the country that leads the global fight against slavery, unable to address it inside its own borders?
There are an estimated 1.4 million sex slaves in the world today - many of them are trafficked from poor countries to wealthy European cities.
It is a form of slavery that is passed down from one generation to the next, enslaving millions in countries such as Pakistan and India. In this episode, Rageh Omaar meets men, women and children labouring in quarries and brick kilns in dangerous conditions and for effectively no pay.
There are at least 8.4 million child slaves in the world today. In Haiti, a practice called 'restavek' sees the children of poor families forced to work as domestic help for wealthier families.
Brazil was once the world's largest importer of slaves from Africa, but it has taken the lead in fighting 21st century slavery with a raft of innovative laws. Slave labour, however, continues to thrive in the South American country, particularly in the age-old practice of charcoal burning.
India has the world's highest number of slaves, among them are an increasing number of women and girls sold into marriage for as little as $120 to men who often burden them with strenuous labour and abuse them.
Over the past 20 years China has become the world's biggest exporter of consumer goods. But behind this apparent success story is a dark secret - millions of men and women locked up in prisons and forced into intensive manual labour.
Rageh Omaar chairs a public debate in which he and a panel of those most closely involved in the issue of 21st century slavery discuss the scandal of a trade that refuses to die.