As the first human rights issue to provoke wide international, slavery is perpetuated by traditional practices such as child and forced marriage, and by the fact that almost half the countries in the world have yet to criminalize it.

According to the latest UN figures, 40 million people were living in a state of modern slavery in 2016. One in four children are in forced labour, and about 98 per cent of women who are in forced labour have also been subjected to sexual exploitation.

Deeply rooted in fear, with victims often “not realizing” they’re enslaved, it becomes "invisible", and "clandestine”, leaving victims unprotected, said Urmila Bhoola, Special Rapporteur on Contemporary Forms of Slavery, who sat down with UN News's Ana Carmo to talk through its causes and consequences.