Malaysia: Lang & Deer Caves at Mulu NP
Lang Cave and Deer Cave are two massive caves in the Gunung Mulu National Park, having some of the largest cave halls in the world. Lang is the smaller of the two, it is a typical wet cave with some nice cave formations. Helictites and moon milk are the rare formations. There are also glow worms, almost 2-5 times longer than those found in new Zealand, they wave in the drift that exists in the cave. Deer cave, on the other hand was a monster, the second largest chamber in the world (the largest one is just nearby called Sarawak chamber, but the access there is difficult and takes several days often swimming in underground rivers). As you enter the caves through large openings, you are dwarfed inside by the sheer scale of enormity of the caves. The passageway winds along the bottom while massive stalactite hang above and stalagmites tower on the ground. The path through the cave is 1.5km long and ends in the Garden of Eden, where the roof and walls collapsed to make a large opening (maybe 2 football fields). The cave itself is home to a 3mm bat colony that flies out every night.