The Niah National Park is world famous for the oldest human remains in South-East Asia found in its Great Caves dating back some 40,000 years. The archeologists also found fragments of pottery, stone tools, ornaments and a splendid set of wall painting of red-haematite depicting activities of stick-like men with hunting weapons and boats. The work of the unknown artist, estimated to be 1000 years old, still beckon travellers from around the world.

The Niah Cave is accessible by road from Miri of Bintulu. It takes two hours from Miri and three hours from Bintulu of the Park Headquarters at Pangkalan Batu. This is followed by a 45-minute walk along plankwalk of 3 kilometres long to reach the entrance of the Great Caves without getting your feet wet when strolling through the dense tropical vegetation.

Millions of bats and swiftets made the dark recesses of the Niah Caves their home. Along the way, a common scene is meeting workers collecting guano, the accumulation of bird and bat faeces for use as fertilizer. The caves are also known as a site where edible birds' nests could be gathered. Birds' nests made out of the glutinous saliva of millions of swiftlets are also collected by labourers who risk their life to rich the ceiling of the caves at a height of some 50 metres or higher.