The mouth of Niah's Great Cave is enormous enough to hold a cathedral — a dark, cool opening into limestone hills that has sheltered human life for an extraordinary length of time. Excavations here in the 1950s uncovered a human skull dated to roughly 40,000 years old, among the oldest modern human remains found anywhere in Southeast Asia, and pushed back the timeline of human settlement in Borneo by tens of thousands of years.
Deeper into the cave system is the Painted Cave, where faint ochre drawings and 'death ships' — boat-shaped coffins used in ancient burial rites — still line the walls. For centuries the caves have also been harvested for swiftlet nests, prized for bird's nest soup, and for guano used as fertiliser; both trades continue today under strict permits.
Getting to the Great Cave from the park entrance means a walk of a few kilometres along a raised plank walkway through lowland rainforest, which is half the experience — keep an eye out for hornbills overhead and the occasional troop of monkeys crossing the boardwalk ahead of you.