Refugees load their belongings onto a truck as they prepare to return to the Nuba mountains from Yida camp in South Sudan's Unity State, April 20, 2013. The camp, with about 72,000 registered refugees according to the United Nations High Commissioner for Refugees (UNHCR), is considered to be one of the most challenging in the world. REUTERS/Andreea Campeanu (SOUTH SUDAN - Tags: SOCIETY EDUCATION)