The place is the Gomantong Caves in Sabah, Sandakan to be exact.
Why the Gomantang Caves made the list..
Simud Hitam (Black Cave) and Simud Putih (White Cave) are the two dark cave complexes in the Gomantong cave system. Simud Hitam is up to 295 feet (90 meters) high and is more accessible than Simud Putih. The caves are surrounded by a forest having various animals, including orangutans. However, the thousands of live bats, Malaysian cockroaches and huge Scutigera centipedes give way to layers of waste and remains of dead creatures, with rats feeding on them, making this space extremely mucky.
The Gomantang Caves is actually one of Sabah's many attractions. Located in the heart of the Gomantong Rainforest Reserve, the caves have been claimed by the World Wildlife Foundation to be the best managed edible birds' nest cave in the world and has been the focus for birds' nest for many centuries.
They are not as scary as it's made out to be if you enjoy caving or don't mind creepy-crawlies like coaches and centipedes, bats, swiftlets and such. Oh yes, wild orangutans as well in the vicinity.