Located on the Southwest of Sandakan, the Gomantong Caves has considerable historical depth. For centuries, bird nests harvested here are being exported to China where it had been and still is an expensive delicacy. In the olden days, Menangol - a narrow tributary of the Sungai Kinabatangan (Kinabatangan River), is the only way to the caves, but today it can be reached by road.

The Gomantong Caves has two complexes - Simud Hitam and Simud Putih. The easy accessible Simud Hitam, which rises to 90 metres high, produces inexpensive black nests made from hardened swiftlet saliva mixed with feathers, while Simud Putih is harder to reach but produces white nests, which can fetch as much as US$500 per kilo.

During the periods of February to April and July to September when the nests are being harvested, visitors get to see how experience locals with just the use of rattan ladders, ropes and poles, remove the bird nests from the caves' walls.