Gunung Mulu National Park

Gunung Mulu National Park is famous for its limestone karst formations. Features include enormous caves, vast cave networks, rock pinnacles, cliffs and gorges.

Gunung Mulu National Park has the largest known natural chamber or room - Sarawak chamber, found in Gua Nasib Bagus. It is 2,300 feet (700 m) long, 1,300 feet (396 m) wide and at least 230 feet (70 m) high. It has been said that the chamber is so big that a Boeing 747 jumbojet can fly directly into the mouth of the cave and hundreds of metres' down into the ground. The guides at Gunnung Mulu also say that Deer Cave [another large cave] is big enough to fit St. Peter's Basilica inside.

Other notable caves in this area are Benarat Cavern, Wind Cave, and Clearwater Cave;which contains parts one of the worlds largest underground river systems.
Mulu's limestones belong to the Melinau Formation and their age is between 17 and 40 million years (Late Eocene to Early Miocene).

Stratigraphically below the limestones, and forming the highest peaks in the south east sector of the Park including Gunung Mulu, lies the Mulu Formation (shales and sandstones). The age of these rocks is between 40 and 90 million years (Late Cretaceous to Late Eocene).