Gunung Mulu National Park

Gunung Mulu National Park lies in the Miri Division of Sarawak, Malaysia, on the island of Borneo, and protects a mountainous equatorial rainforest built on karst limestone around three peaks, Mulu, Api and Benarat. Its 295 kilometers of explored cave passages include Deer Cave, the largest known cave passage in the world, Clearwater Cave, the longest cave system in Southeast Asia at over 226 kilometers, and the Sarawak Chamber, one of the largest known underground chambers, all first opened to serious scientific study by a 1977 to 1978 Royal Geographical Society expedition that began an ongoing research program. The park's biodiversity is equally significant, recording about 3,500 vascular plant species, 81 mammal species and 270 bird species, along with millions of resident bats, and UNESCO inscribed it as a World Heritage Site in 2000.