The kidnapping of the Chibok schoolgirls in 2014 drew the world's attention to the Boko Haram insurgency.

Of the 270 students taken from the northeastern Nigerian town, about 60 have escaped. Dozens others have since been released after negotiations. The militant group is believed to still be holding about around 100 captive. Last month, Boko Haram released a video purportedly showing some of the girls in custody. More than 20-thousand people have been killed and two million forced from their homes since the militant group began its insurgency in 2009.