Sumatra is as rugged as it gets. Thick rainforests cascade like water down towering peaks. Jungle treks are a struggle with gravity and mud. But rewards are plentiful: the world's largest flower, one of the last remaining enclaves of orang-utans, or the sulfur-spouting crater of a resting volcano.

Sumatra is rich in natural resources (timber, gas and oil), but very little of the profits are reinvested in the island's economy. The Indian Ocean tsunami in 2004 and earthquake in 2005 levelled large parts of Aceh and Nias, respectively, and rebuilding infrastructure and livelihoods is slow going.