Bukit Lawang is a small riverside village on the edge of Gunung Leuser National Park in northern Sumatra, the best place in the world to see wild Sumatran orangutans in their natural forest habitat. The semi-wild orangutans habituated at the former rehabilitation centre still visit the feeding platforms, offering close encounters, while multi-day jungle treks deeper into the park may reveal the critically endangered Sumatran tiger, sun bears, Thomas's leaf monkeys, and the rafflesia — the world's largest flower. Tubing down the Bahorok River after a sweaty jungle trek is one of Sumatra's great pleasures.