Atlanta, (CNN) - Across the world, man's inhumanity is secretly on show wherever human traffickers prey on those who are vulnerable. But there is also hope and inspiration in the stories of survivors, and the dedicated, but under-resourced, anti-traffickers.

For four years, Robert Bilheimer documented their stories in Europe, North and South America, Asia, and Africa for the documentary "Not My Life" which airs on CNN International this weekend.

CNN sat down with the Oscar-nominated director to talk about the horrors of human trafficking and the uplifting tales of the survivors he met while filming.

CNN: Who are human traffickers?

RB: Human traffickers are lazy, amoral, essentially small-time criminals who earn their profits on the backs, and in the beds, of our planet's youth.

They are modern-day slave traders. They commit unspeakable, wanton acts of violence against their fellow human beings, and are rarely punished for their crimes. They are the great plague of the 21st century.

CNN: Is there one example you remember most from all the horror stories you heard about traffickers and their crimes while filming "Not My Life?"

RB: In the film, there is an interview that describes the following practice in an Eastern European country.

Before shipping a new recruit of girls to the capitals of the west - Rome, Paris, Madrid - the traffickers would round them all up in a room. They would pick one girl, bring her in front of the group, and then summarily execute her: either burn her alive, or a bullet through the mouth. This is the way these particular traffickers would say to the other girls: "Don't try to escape."

There are thousands of stories like these, in different contexts, all over the world. Unspeakable violence is integral to the practices of human trafficking and modern slavery.

CNN: You describe traffickers as small-time criminals, and yet this has become a very big-time industry.

RB: Correct. The number put forth by the experts is about $32 billion a year globally. This rivals other criminal industries, like the gun and drug trades. But in this case it's human beings who are the commodity.

CNN: So the profits are huge, but "organized crime" is not the main player like with drug cartels, for instance.

RB: Precisely. That's what makes it so dangerous and elusive. It's basically a vast network of clever "sweet-talkers" as the traffickers are often referred to by their victims.

Where you find a poor family in Ghana, there you find a sweet-talker offering a desperate mother a couple of hundred dollars to feed her family and teach one of her boys "a trade." The boy disappears overnight and becomes a slave, forced into labor of various kinds.

Where you find a poor fishing family on the banks of the Mekong river, there you find a sweet-talker whisking an eight-year-old girl away to work in a brothel in Phnom Penh, where she is raped and sewn back up again, so that men from Japan and the United States will believe, because of her bleeding, that she is a virgin.

Where you find a girl in the heartland of America who might be having "normal teenage problems," as Angie says in "Not My Life," there you find a sweet-talker who looks like the boy next door - and sometimes is - ready to give that girl a ride. But the ride is not home. It is three states away to a truckstop, where the girl is forced, on pain of death, to perform dozens of sex acts every night.

Natural disasters such as the earthquake in Haiti? A feast for traffickers.

Generational poverty such as we find in the poorest states in India? Bread and butter for those who practice indentured servitude.

The list goes on and on.

CNN: Any successful business - and this is what you are describing - operates on the law of supply and demand.

RB: Take the sexual trafficking of young girls. If you didn't have millions of men all over the world willing to pay money to have sex with children, you wouldn't have this massive problem we have now. The demand is relentless. And as the U.S. anti-trafficking ambassador, Luis DeBaca, says it's not just sailors off a ship anymore. It's the beat, beat, beat of airplanes landing every day.

It's also, I might add, the click, click, click of fingers tapping at computer keyboard keys. Human trafficking is ultimately a story about the way the world is.

CNN: How do people come back from being trafficked?

RB: I am not an expert in psychological, physical, or social rehabilitation, so I can only tell you what I have observed after four years of being with hundreds of victims and survivors.

What I have seen is miraculous. There is no other word for it. After the all the injustice, suffering, and cruelty, these horribly abused children have shown a resilience, spirit, and ability to heal and "come back", as you say, that I honestly do not know how to explain.

But it is deeply inspiring. It gives me the feeling that in the age-old battle between good and evil, good will triumph in the end, even though we have a tough road ahead. This is what I have learned from the journey of "Not My Life." The human spirit is a powerful thing indeed.

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