Mulu National Park, located in the Malaysian State of Sarawak on the island of Borneo, is a UNESCO World Heritage Site. It is Sarawak's largest national park, home to the world's largest cave chamber, the largest natural chamber and the longest cave passage. It is outstanding both for its high biodiversity and for its karst features. The park is dominated by Mount Mulu, a 2,376 m-high sandstone pinnacle and the property is the most studied tropical karst area in the world. It is also the second highest mountain in Sarawak. The geological Melinau Formation contains a remarkable concentration of caves, revealing a geological history of over more than 1.5 million years.

High in endemism, Mulu National Park provides significant natural habitat for a wide range of plant and animal species, both above and below ground. The 52,865 ha park contains seventeen vegetation zones, exhibiting some 3,500 species of vascular plants. Its palm species are exceptionally rich, with 109 species in twenty genera recorded, making it one of the worlds richest sites for palm species. Providing protection for a substantial area of Borneo’s primary tropical forest and a home for a high diversity of species, including many endemics and threatened species, the large cave passages and chambers provide a major wildlife spectacle in terms of millions of cave swiftlets and bats.

The property is home to one of the world's finest examples of the collapse process in karstic terrain and provides outstanding scientific opportunities to study theories on the origins of cave faunas. The deeply-incised canyons, wild rivers, rainforest-covered mountains, spectacular limestone pinnacles, cave passages and decorations found within the property produce dramatic landscapes and breathtaking scenery that is without rival.

Important both for its high biodiversity and for its karst features, Mulu National Park, on the island of Borneo in the State of Sarawak, is the most studied tropical karst area in the world. The 52,864-ha park contains seventeen vegetation zones, exhibiting some 3,500 species of vascular plants. Its palm species are exceptionally rich, with 109 species in twenty genera noted. The park is dominated by Gunung Mulu, a 2,377 m-high sandstone pinnacle. At least 295 km of explored caves provide a spectacular sight and are home to millions of cave swiftlets and bats. The Sarawak Chamber, 600 m by 415 m and 80 m high, is the largest known cave chamber in the world.