America has a growing sex trafficking problem and the city of Atlanta has been identified as one of the hotspots.
In this big southern city, a cultural and economic powerhouse, the illegal sex trade is worth about $300m (£230m) a year.
The FBI has also named it as one of the worst places in the US for child sex trafficking.
But the city is finding ways to fight back against this form of modern slavery.
Street outreach worker Kasey McClure showed us the notorious Fulton Industrial Boulevard area.
She pointed out the young women hanging around the garage forecourts and in the doorways of rundown hotels, shadowed by pimps.
Some were visibly pregnant.
Kasey said that most would be forced to have sex a minimum of five to six times a day.
“They’re getting beat up; we’ve had girls who’ve had all their teeth knocked out,” she said.
“You know, how can they get off the street and get a decent job when they can’t even smile?”
Kasey hands out toiletries and her phone number to girls.
As we drive, a 16-year-old rings from a nearby motel room, desperate for help.
“I don’t have no food, I’m hungry, I haven’t eaten since yesterday,” she pleads.
Kasey organises a safe house quickly, and says it is common for pimps to withhold food until a girl makes them enough cash.
Sex trafficking survivor Alainah Beretti told us her story.
She was controlled by a pimp from the age of 17.
He took photos of her holding teddy bears and marketed her for sex with men who knew she was young.
She said: “It’s not just sex. You’re opening your soul to every John you sleep with. I’m scarred, and I’ll be scarred for life.”
Atlanta is attractive to traffickers for a number of reasons. One is its thriving adult entertainment industry.
But a small network of former and current strip club employees are trying to make a difference.
Heidi Cloud manages the dancers at The Pink Pony club and has lots of “tricks” on her application form to detect those who might be working against their will.
She also shares information with other clubs about known pimps and makes sure they don’t get past the bouncers.
She said: “We’ve got to stop pimps from getting in to the club and stop pimps from getting their girls in to the club, because once the girl gets in to the club it can further spread recruiting of other girls as well.”
Atlanta also attracts traffickers because it is a major transport hub.
The airport here is the busiest in the world.
Its head of security, Jan Lennon, has launched a campaign to deter traffickers who use the huge crowds as cover, sometimes flying in and out with a victim before anyone knows what’s happened.
“We are on a mission,” she said.
“What we say is ‘humans are not for sale, not then, not now, not ever’.”
The airport is also training every one of its thousands of employees to spot the signs of a potential victim.
Jan works closely with Donna Hubbard, who runs a trafficking awareness group called Airline Ambassadors.
“You will see people who are not in control of their personal documents, who are not allowed to answer questions for themselves.
“They may seem anxious or afraid.
“They may not know where they are going or even who is picking them up.”
Several major motorways converge on this big city making it easy to move and hide victims.
But a group called Truckers Against Trafficking is trying to make that stop.
Driver Stephen Richardson has been trained to spot the signs and call the national trafficking hotline.
He said: “When these girls approach your truck the main question is ‘do you even know where you are?’ That’s a main sign.
“If they don’t know where they are, if they look drugged, look for tattoos showing they belong to someone. They mark these girls like they are pieces of material.”
Victims of sex trafficking are usually young, and they are often children.
The charity Street Grace works to end the demand for child sex, a problem often made worse by the thousands of visitors who come for the region’s many big events and conventions.
The scale of the problem is hard to measure, but the estimates that do exist are startling.
Its CEO, Bob Rodgers, said: “The latest research that we have says that on any given night in the state of Georgia, 300 plus or minus kids are being sold for sex.
“If you want to know what a purchaser of sex looks like… it looks like you, it looks like me… the statistics tell us that, the arrest records tell us that.
“This is not some problem that’s happening overseas, it’s happening here.
“This is happening to our children… in our neighbourhoods, in our communities, in our places of work.”
The FBI’s field office in Atlanta is home to the nation’s largest anti-child sex trafficking task force.
Supervisory Special Agent Eric Pauley told Sky News: “It’s money. Money is the motivator here.
“The average age of entry… that we see for children having entered this lifestyle is approximately 14.
“They are vulnerable children and these traffickers feed off that vulnerability much like any predator would.”
Sex trafficking isn’t just a problem in Atlanta.
It has been estimated that apart from all the adults involved, up to 300,000 American children are at risk of being trafficked for sex every year.
Globally, it is a growing problem.
UNICEF says human trafficking is now the second largest criminal industry in the world, worth $32bn (£25bn)