From lush primary rainforest with an incredible biodiversity, to one of the world’s largest cave systems underneath, Mulu National Park never ceases to amaze its visitors. In fact so much so, that Mulu National Park was added to the list of UNESCO World Heritage Sites in the year 2000. To achieve that, natural sites must be of outstanding universal value and meet at least one out of four criteria. Mulu did not just tick one of the boxes, but all four!

A 15-month multidisciplinary scientific expedition in Mulu in 1977/78, comprising of a team of more than 100 scientists and researchers, made astonishing discoveries: More than 2500 plants were identified, 60 mammals and 320 fish species were described and the number of insect species was estimated at a number of 12.000. A caving team explored more than 40km of caves and underground passages, including the world’s largest cave passage. And yet it provided merely a glimpse into the extensive underground landscape of Mulu. Subsequent expeditions in the years to follow have revealed many more spectacular cave chambers and passages, including the Sarawak Chamber (the largest underground chamber in the world), Deer Cave (the world’s largest single cave passage) and Clearwater Cave (the largest interconnected cave system), which at present measures a length of more than 255 km. To date a mind-blowing total of mora than 360 km of caves and passages have been explored and mapped in Mulu, with likely much more to come.

A wide range of tours offers visitors the chance to marvel at the outstanding natural wonders of Mulu: From exploring the caves underground to the challenging climb of Mount Api with breath-taking views of the Pinnacles, a series of 45-meter-high razor-sharp limestone spikes, which tower majestically above the surrounding forest.