Gunung Mulu National Park is one of Nature's most spectacular achievements and the 'jewel in the crown' of Sarawak's expanding network of national parks. It is also the largest national park, covering 52,865 hectares of primary rainforest, which is criss-crossed by fast flowing rivers and clear jungle streams. Mulu is dominated by three mountains - Gunung Mulu (2,376 m), Gunung Api (1,750 m) and Gunung Benarat (1,585 m). Yet many of Mulu's greatest attractions lie deep below the surface. Hidden underneath the forested slopes of these mountains is one of the largest limestone cave systems in the world.

This system, a breath-taking natural wonder, contains a number of record breaking caves. With the world's largest cave passage (Deer Cave), the world's largest natural chamber (Sarawak Chamber), and the longest cave in Southeast Asia (Clearwater Cave), it is not surprising that Mulu is now world-famous. Over 200 km of cave passages have been surveyed but this is thought to represent just 30-40% of the actual total.

The oldest of Mulu's caves started to form about 5 million years ago when sideways earth movements resulted in the formation of both limestone and sandstone mountains, lying side by side. Millions of years of heavy rain and the action of rivers and running water carved out the vast subterranean system that exists today. The weathering process still continues; dripping water creates new rock features, limestone is slowly worn away, and underground rivers carve and sculpt the caves, transporting limestone debris to the cave mouth or redistributing it within the system.

Although Mulu is synonymous with caves, the 'Mulu experience' is not limited to underground attractions; above ground there is plenty to see and do. The park is covered in rich primary rainforest and offers a whole range of nature-based activities. There are some excellent jungle treks and mountain hikes, including the challenging trek to view the Pinnacles - 45 metre high, razor sharp limestone spikes that sit majestically on the slopes of Gunung Api.

With it's rich bio-diversity, and world-famous caves, Mulu offers the adventurous traveller an exhilarating cave and rainforest experience, possibly unmatched anywhere else on Earth.

Mulu's four Show Caves were selected for their uniqueness or sheer beauty. They can all be visited as day trips from the park HQ and are accessible by plankwalks and well-lit concrete paths. Strategically positioned spotlights highlight the unique features of the individual caves. A plankwalk leads through the forest to Deer and Lang's Cave whilst Clearwater Cave and Wind Cave are reached by taking a longboat up the Melinau River, or by following a 4 km nature trail. The more adventurous can do Adventure Caving.

The climb to the summit of Gunung Mulu (2,376 m) is the toughest organised trek in the park. It requires a high level of fitness and a sense of adventure. Indeed, Gunung Mulu has always attracted adventurers. In the 19th Century, Spenser St John and Charles Hose, two old 'Borneo hands', attempted to conquer Mount Mulu. They and other explorers and mountaineers failed. It wasn't until the 1920's, when a Berawan rhino hunter named Tama Nilong discovered the 'south-west' ridge, that a way to the summit was found. In 1932, Tama Nilong led Lord Shackleton and an Oxford University Expedition to the summit of Mulu.