Urban Refugees in Nairobi, Kenya.

NAIROBI, KENYA - MAY 22, 2013: A young refugee boy sneaks a nap on his parent's bed. When night comes he will sleep on a mattress the same size - but on the floor shared with five other children. This family tries to live a low profile in one of Nairobi's slums where refugees must navigate the many dangers of urban life plus many more dangers because they are not citizens. Children are at risk for human trafficking and sexual assault. Half of Africa's 2.5 million refugees now live in cities - marking a major migration shift from camps to urban centers. Living in the shadows of Africa's slums are the newest faces of the world's changing refugee crisis: urban and alone. (Photo by Amy Toensing/Corbis via Getty Images)