Warlords such as Ismail Khan, operating out of the western province of Herat, siphon off customs revenue at source, sending only a fraction of the receipts to Kabul.

ECONOMIST: Now the country's fragile peace must be made to stick

China is the biggest source of visitors, sending over half a million of them last year.

ECONOMIST: Tourism could do a lot of good if Vietnam handles it properly

Twitter has emerged as a vital source of this real-time information, with more than 100 million users sending 250 million tweets every day on virtually every topic.

BBC: Screenshot of Google+