A child gold miner in Watsa, northeastern Congo. 2004 Marcus Bleasdale hide caption

toggle caption Marcus Bleasdale

U.S. Border Patrol agent Richard Funke looks for footprints from illegal immigrants crossing the U.S.- Mexico border near Nogales, Ariz., in 2010. John Moore/Getty Images hide caption

toggle caption John Moore/Getty Images

Brazilian slave laborers stop their work to listen to a Labor Ministry inspector explain their legal rights, on the Bom Jesus farm in the Amazon basin in 2003. Rickey Rogers/Reuters /Landov hide caption

toggle caption Rickey Rogers/Reuters /Landov