One of the biggest limestone cave systems in the world is Mulu Caves, in Gunung Mulu National Park in Sarawak. The caves were formed over 60 million years. At one point Mulu Caves were undersea, that, and the relentless process of weathering by the elements of rain, sun and time shaped the landscape we see at Mulu today. Limestone pinnacles and bleached white is the identity of Mulu Cave with big chambers for the passage of wind. This system, a breath taking natural wonder contains a number of record breaking caves. With the world's largest cave passage (Deer Cave), the world's largest natural chamber (Sarawak Chamber), it is not surprising that Mulu is now a world-famous UNESCO Heritage site. Over 200 km of cave passages have been surveyed but this is thought to represent just 30-40% of the actual total.
Here is a list of caves which you can visit at Mulu Caves:-
Clearwater Cave is known to be 107 kilometres long and claimed to be the largest in South East Asia. Tourists often visit only a small portion at the mouth of the cave. Within this area they can see the Lady's Cave. The Lady's Cave has fine limestone formations. The other passage which is at the left of the cave which is easily accessible to visitors, leads to an underground stream. Along this passage visitors can see intricate formations about 100 metres above them.
Deer Cave is reached by following a three kilometre plankwalk which passes through peat swamp, alluvial flats and limestone outcrops. There is much to see on the way to the cave, including some superb rainforest, jungle streams and an ancient Penan burial cave. When you reach the cave entrance you are left in no doubt that you are about to enter the largest cave passage in the world. Deer Cave is simply huge - it is just over 2 kilometres in length and never less than 90 metres high and wide.
Lang's Cave is the smallest of the show caves but its rock formations are well worth seeing. These are made all the more attractive by the strategically positioned spotlights which highlight stalactites and stalagmites. As the cave is relatively small and well-lit, it offers good opportunites to see some of its inhabitants such as bats, swiftlets and even cave-dwelling snakes.
Wind Cave is aptly named as a constant cool "breeze" comes from inside the cave. The visitor can experience this as soon as he steps at the mouth of the cave. At the entrance at the "upper deck", the cool breeze is even stronger, and it is extremely refreshing after the climb along the walkway from the river. Only the entrance part of the cave is accessible to the visitor. To go beyond would require a boat and depends on the water level and needs powerful lighting.
Racer Cave, this cave caters more to an intermediate thrill seeker as it involves climbing up and down passageways using ropes. Insects and Racer snakes can be found in this cave.
To get to Gunung Mulu National Park most visitors will either fly into Mulu Airport via regular scheduled flights departing either from Miri, or Kota Kinabalu (capital of Sabah).