Families wait for hours to register at the Yida refugee camp in South Sudan along the northern border in early July. Within a few weeks, the population of the camp more than doubled, leading to shortages of food, water and medicine. Paula Bronstein/Getty Images hide caption

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The South Sudan delegation, including Vice-President Riek Machar Teny-Dhurgon (second from right), are congratulated by a delegate as they take their seats after the U.N. General Assembly voted to admit the newly formed nation. Stan Honda/AFP/Getty Images hide caption

itoggle caption Stan Honda/AFP/Getty Images