When Mejgon was 10, she went to work in a tomato-juice factory to support her father’s drug habit.

When she was 11, her father sold her to a 60-year-old man for two boxes of heroin.

After enduring years of abuse, she escaped to a women’s shelter in Herat, Afghanistan, where photographer Stephanie Sinclair met her in 2004.

“I don’t know what the meaning of love is. . . ,” the 16-year-old tearfully confided to Sinclair. “In my whole life, I have never felt it.”

photo: Stephanie Sinclair/ VII ©2012

“I couldn’t even imagine what that would be like,” said Sinclair, who has devoted the years since to documenting the harmful practice of child marriage.

Child marriage is common in more than 50 countries in the developing world, and Sinclair has traveled to many of them, including Afghanistan, Yemen, India, Nepal and Ethiopia. Many of the girls she encounters, like Mejgon, share personal tales that are simply heartbreaking. But others, backed by members of their communities who see the value in letting little girls grow up, face more hopeful futures.

This summer, Sinclair sat down with Christiane Amanpour, host of her own program on CNN, to discuss her work on this heart-wrenching topic.

“You can hardly believe this is real,” said Amanpour, looking at one of Sinclair’s photographs from Afghanistan. “This ancient man with this child who barely looks like she’s 5.”

During the 10-minute interview, Sinclair discusses how she received access to these girls, why families marry them off when they’re so young, the impact on the girls and their communities, and why the project has been so important to her.

“It’s a harmful traditional practice that is slowly changing,” she tells Amanpour. “We just want to have it change even faster.”

You can watch the interview for yourself here. Sinclair’s award-winning work will be on display as part of the Too Young To Wed exhibit at the United Nations, which opens on Oct. 11, 2012, the first International Day of the Girl Child.

Her photos documenting child marriage and its consequences have gained widespread attention, appearing in multiple publications and venues, including National Geographic, The New York Times Magazine and at the Whitney Museum of American Art.