Why is peace in South Sudan so elusive?
The challenges inherited by South Sudan when it attained independence in 2011 are often forgotten, the head of the UN mission in South Sudan, David Shearer, has said.
"I don’t think people really understand where South Sudan started from,” he told BBC Hardtalk. “There is 200km of tarmac road in South Sudan - 200km in a country the size of France.”
Civil war in South Sudan has displaced millions and prompted famine in parts of the country.
You can see the interview in full on Friday 2 June on BBC World News and the BBC News Channel and after on BBC iPlayer (UK only)