In Iraq and Syria,backed by the U.S. And now hundreds of young women who went to marry ISIS fighters are desperate to go home to Europe.
Sarah is a French citizen who traveled to Syria when she was just 18, married an ISIS fighter and had a baby.
Three years later, though, Sarah's had second thoughts
Her husband was killed, she's run away from the extremists, and she wants to take her baby back to France.
She told us she wants to forget everything and get her life back. She wants to start again and protect her daughter.
She's one of hundreds of young, European women who joined ISIS -- some of them just teenagers -- easily lured to Syria with false promises of a romantic life in the so-called Islamic State.
Along with other foreign defectors, Sarah and her daughter were given shelter by a moderate rebel group in northern Syria.
But one of their leaders, Mohammed Adeeb, said it's difficult to persuade foreign governments to accept the defectors back.
Adeeb said they've tried to communicate with several governments, but they either get no answer or nothing positive.
In Paris, Moumenah al-Hariri is a negotiator hired by Sarah's family to try to bring her home.
She told us all the women she helps know that they have to go to prison once they're back -- including Sarah.
Moumenah says she only helps women and children -- negotiating with European governments and using her contacts in Syria.
She says they're a threat if they're left in Syria.
"That's when they become a danger," she says. "They're widows, so their children can be taken from them at any moment -- brainwashed, radicalized and turned into human bombs. The children have a right to a second chance."
The Syrian rebels who gave refuge to Sarah when she fled ISIS told us they've also been sheltering 20 other defectors -- all from Western countries.