There is a cave group which also becomes a length of 195km in all in a Gunung National Park.
The "Deer cave" in it is longest cave in the world, and the "Sarawak cave" is largest cave in the world.
So, 60% of the cave is not investigated yet.

Although the Mulu mountain with a Gunung Mulu National Park was made of sandstone, since the layer of a limestone was made by ancient diastrophism, the limestone cave was made.

And, various animal like a bat and the plant, insects live, in addition about 180 sorts of orchid live, too.

It was registered in 1993.