Sarawak Chamber is the largest known cave chamber in the world. It is in Gua Nasib Bagus (Good Luck Cave), which is located in Gunung Mulu National Park, in the Malaysian state of Sarawak on the island of Borneo.
The chamber was discovered by three British cavers, Andy Eavis, Dave Checkley and Tony White, in January 1981 during the Mulu'80 Expedition. The story of how it was discovered is told in the books Underground Worlds and Giant Caves of Borneo.
Later named Sarawak Chamber, it measures 600 m (1968 feet) long, 435 m (1,312 feet) wide and a maximum of 115 m (377 feet) high, and was estimated as three times the size of the Big Room in Carlsbad Caverns National Park, New Mexico, then thought to be the largest underground chamber. Its volume and area were checked by laser scanning in 2011 and were found to be 9,579,205 m3 and 164,459 m2 respectively. 
To reach Sarawak Chamber, one must follow a river upstream from the cave entrance. This long passage has a roof up to 60 metres high, and may require some swimming and a traverse along a ledge. Accompanied visits can be arranged by the national Park.
Geology and formation
The chamber is due to two main factors. The first of which is uplift in the soil, occurring between 2 and 5 million years ago. The second is the erosion of the soft limestone and other rocks, and coupled with high rainfall of the surrounding rainforest, these processes made the chamber we see today.
- Kirby (2011:23)
- Gunung Mulu World Heritage Area, Cave activities
- Kirby, Matt (2011), Mulu Caves 2011, Mulu Caves Project.
- Jackson [ed], Underground Worlds (1985) Time Life Books. Earth Series.
- Meredith, Wooldridge and Lyon, Giant Caves of Borneo (1992) Tropical Press.
- Facts and Fallacies - Stories of the Strange and Unusual (1989). Reader's Digest Ltd. pp. 14–15. ISBN 0-86438-087-9.
- Extreme Earth Collins (2003) Pp. 78–79. ISBN 0-00-716392-4
- House of Leaves (2000) p. 125.
- Description of the Sarawak Chamber at the Mulu Caves project.
- Surveying Sarawak Chamber at Sarawak Caves
- Short description at www.showcaves.com.
- World's Largest Cave - Sarawak Chamber