Two female detainees sleep in a holding cell as the children are separated by age group and gender at the U.S. Customs and Border Protection Nogales Placement Center in Nogales Arizona

Two female detainees sleep in a holding cell, as the children are separated by age group and gender, as hundreds of mostly Central American immigrant children are being processed and held at the U.S. Customs and Border Protection Nogales Placement Center in Nogales, Arizona, June 18, 2014. REUTERS/Ross D. Franklin/Pool