The first thing one notices on the streets of Juba, the capital, is the abundance of white Toyota Land Cruisers. There are fewer than 100 kilometers of tarmac roads in the entire 240,000-square-mile country; one cannot move around without a four-wheel-drive vehicle. A closer look at the Land Cruisers reveals that most have special license plates: UN for United Nations vehicles, and GOSS for tho...