Just four years after South Sudan was granted independence, becoming the world's newest country, it has descended into chaos and conflict. The fighting, mostly along ethnic lines, has created one of the world's largest humanitarian crises. Thousands have been killed, more than two million people displaced, and the country is on the brink of famine. Our World's Yalda Hakim travels deep into rural South Sudan - where no Western journalist has been. She meets traumatised people, some on the verge of starvation.