Penan family, Mulu expedition, Borneo, Indonesia, Southeast Asia, Asia

Penan Man making blowpipe darts, Mulu expedition, Indonesia, Asia

Member of the Penan tribe with blowpipe, Mulu expedition, Sarawak, island of Borneo, Malaysia, Southeast Asia, Asia

The giant caves of Mulu National Park, Sarawak, Borneo, Malaysia

The giant caves of Mulu National Park, Sarawak, Borneo, Malaysia

The giant caves of Mulu National Park, Sarawak, Borneo, Malaysia

Cave explorers add scale to a cave in Mulu National Park

The giant caves of Mulu National Park, Sarawak, Borneo, Malaysia

The giant caves of Mulu National Park, Sarawak, Borneo, Malaysia

A cave explorer admires pretty cave formations in Mulu National Park.

A cave explorer poses in a tube in a cave in Mulu National Park

Three cave explorers tackle a steep rubble slope on their way to an underground camp in a cave in the jungle of Mulu called Whit

Two female cave explorers walk through a tunnel in a cave deep in the Malaysian jungle in Mulu.

Photograph of a huge underground ramp deep in the heart of the mountain in Mulu National Park.