Somewhere beneath the rainforest of Borneo is a single room so large that a fleet of airliners could be parked inside it with space left over. Sarawak Chamber covers 154,530 m² of floor — close to 38 acres of rock buried under a mountain — and it is only the start. The twelve chambers below are the largest single voids ever surveyed underground, scattered from Malaysia and China to Spain, Iran, Oman, Romania, Belize and Papua New Guinea. They are ranked by floor area, the flat plan measurement Guinness World Records certifies and the only metric surveyed consistently enough to sort a list this deep; rank by volume and the top two swap, because China's Miao Room encloses more space than any chamber on Earth while Sarawak covers more ground. Every chamber here is a natural void that exists today, and the figures come from cave surveys — the best laser-scanned, the rest estimated from length, width and height.
12 Biggest Cave Chambers in the World (2026)
The record The biggest cave chamber in the world is the Sarawak Chamber, in Malaysia — 154,530 m² (1,663,347 sq ft), floor area. Source: Guinness World Records. Verified .
Biggest Cave Chambers in the World The Ranking at a Glance
Fun Facts About the World's Biggest Cave Chambers
- Two different chambers can each claim to be the world's biggest. Sarawak Chamber covers the most ground, while Miao Room in China encloses the most space — one record is measured in square metres, the other in cubic ones.
- Laser scanning has been brutal to old records. An early published estimate put Sarawak Chamber's volume above 16 million m³; when a 3-D scan finally measured it in 2011 the figure came back at 9.58 million, a cut of more than a third.
- The tightest finish on this list is 120 m² — Hong Meigui Chamber edges Titan Chamber by about two parts in a thousand, which is well inside the margin of error of any cave survey. They are best read as joint ninth.
- China holds four of the twelve and Papua New Guinea two, but the list spans eight countries across Asia, Europe, the Middle East, Oceania and Central America.
- Belize is the only entry from anywhere in the Americas. The United States has none: the Big Room at Carlsbad Caverns, the best known giant chamber in North America, covers 33,210 m² — roughly twenty-eighth in the world, and well short of this list's cutoff.
- Majlis al Jinn in Oman has no walk-in entrance at all. The chamber is sealed except for shafts in its roof, so the only way in is to abseil more than 100 m through a hole in the desert floor.
1. Sarawak Chamber
At 154,530 m², Sarawak Chamber is the largest cave chamber on Earth by floor area, a record Guinness World Records still certifies. It lies inside Gua Nasib Bagus — Good Luck Cave — beneath the limestone of Gunung Mulu National Park in the Malaysian state of Sarawak, on Borneo. British and Malaysian cavers found it in 1980, and a laser survey in 2011 finally fixed its dimensions: a sloping, boulder-strewn floor several hundred metres across, with a roof more than 70 m overhead.
Nothing about the chamber is easy to reach. There is no lighting, no walkway and no viewing platform, and the way in follows the underground river that carved it, through cave passage beyond the entrance and up a long boulder slope into the dark. Gunung Mulu National Park runs guided show caves that anyone can walk through, but this is not one of them — Sarawak Chamber is an expedition-grade adventure caving trip for fit, experienced visitors, and even standing inside it you cannot see the far wall.
2. Miao Room
Miao Room covers 140,540 m² of floor, second only to Sarawak Chamber — yet by volume it is the biggest cave chamber in the world, enclosing about 10.78 million m³ of air. It sits in the Gebihe cave system in Ziyun county, in the karst country of Guizhou province, southern China. A French expedition reached it in 1989, but it took until 2013 for a British-led team funded by National Geographic to carry 3-D laser scanners underground and measure it properly.
The gap between the two chambers explains why "biggest cave chamber" has two answers. Sarawak Chamber spreads wider across the ground, while Miao Room is narrower but far taller, its roof arching high enough above a boulder-choked river passage to bank up more total space. Visiting means a caving expedition through the Gebihe system rather than a ticketed tour — Guizhou has spectacular show caves open to the public, but Miao Room is not among them.
3. Sala del GEV
The Sala del GEV spreads across 87,090 m² beneath the Basque hills, which makes it comfortably the largest cave chamber in Europe. It fills almost the whole of the cave known as Torca del Carlista, in the Karrantza valley of Bizkaia, roughly 35 km from Bilbao in northern Spain. Cavers first attempted the shaft in 1957 and reached the floor in 1958, dropping into a single ovoid void around 500 m long, 245 m wide and about 100 m from floor to ceiling.
Torca del Carlista is a pothole rather than a walk-in cave, and that shapes everything about seeing it. The only entrance is a narrow vertical shaft on the Peñas de Ranero, so every visitor arrives on a rope, dropping free-hanging into blackness before a headlamp beam finds the floor far below. The cave lies within the Armañón Natural Park and only cavers may go inside: permission is requested from the provincial authority in Bizkaia, less to ration access than to keep a record of who is underground.
4. Ghar-e-Dosar
Ghar-e-Dosar covers about 81,500 m² of floor, hidden inside a desert mountain in central Iran. It opens high on a ridge of Tang-e-Chenar Mountain near the town of Mehriz in Yazd province, around 1,900 m above sea level, in country so arid that a void on this scale came as a real surprise. Iranian cavers announced it in 2013 as one of the largest cave rooms then known anywhere, and a laser survey in February 2017 mapped it as a broad oval roughly 385 m by 265 m.
The chamber is a single enclosed dome rather than one room in a sprawling system, which is what makes its scale so striking: a lone cavity, entered through a modest opening, that swallows light entirely once you are inside. It lies in remote desert terrain with no tourist infrastructure, no lighting and no marked path, so visiting means travelling with Iranian caving groups who know the mountain. For most people it stays a place seen in survey drawings and expedition photographs.
5. Benua Chamber
Benua Cave holds a single chamber of about 70,500 m², running roughly 470 m along its longest axis, up to 150 m wide and 170 m high. It lies on the Keriaka Plateau above Korepovi village in the Kunua district of north-west Bougainville, the large island at the eastern edge of Papua New Guinea. The cave is one continuous space rather than a chain of linked rooms, and an 18 m stalagmite rises from its floor.
Benua is one of the few chambers here that ordinary visitors have a realistic chance of entering. It has long been known to the communities living below the plateau, and Bougainville has promoted it to adventurous travellers arriving through Buka. Even so, this is genuinely remote country: reaching the cave means a guided walk in with the permission of local landowners, and the measurements quoted for it come from expedition reporting rather than a modern laser survey, so treat its exact figure as the least certain on this list.
6. Majlis al Jinn
Majlis al Jinn — the Meeting Place of the Spirits — is a domed chamber of roughly 61,000 m², about 310 m by 225 m, with a ceiling arching 120 m above the floor. It lies beneath the Selma Plateau in eastern Oman, some 100 km south-east of Muscat and about 1,380 m above sea level. Don Davison and Cheryl Jones located it in June 1983 and surveyed it in 1985, at which point it was the second-largest cave chamber known anywhere in the world.
There is no walk-in entrance. The chamber is sealed but for three shafts in its roof, so the only way inside is to abseil more than 100 m through a hole in the desert floor, landing on a debris cone in a space with no visible walls. That descent made it internationally famous and then cost it: after unsanctioned BASE jumping and the damage that followed, the Omani government placed the cave off limits in 2008, and access has been tightly controlled since.
7. Sala Giganților
Sala Giganților — the Hall of the Giants — measures 59,607 m² of floor, making it the largest chamber in Romania and, by most reckonings, the second largest in Europe after Spain's Sala del GEV. It lies deep inside Sistemul Humpleu, a cave system in the Firei valley of the Apuseni Mountains in Cluj County whose surveyed galleries run to more than 40 km. The hall is long and comparatively low for its size, a broad flat-floored space rather than a soaring dome.
Humpleu is a protected cave and not a show cave: no lighting, no paths, no public entrance, with Romanian caving clubs controlling access to keep its formations intact. Proposals have circulated to open part of the system to visitors, but for now the Hall of the Giants is reached only by permitted cavers working alongside the clubs that mapped it. The Apuseni Nature Park around it is open to anyone, with marked trails and several accessible show caves nearby.
8. Cloud Ladder Hall
Cloud Ladder Hall covers 57,460 m² and is tall enough to make its own weather, which is how it got its name. The chamber sits within Er Wang Dong, a cave system beneath Houping in Wulong District, Chongqing municipality, in the karst mountains of south-western China. Its roof stands hundreds of metres above the floor — high enough that mist gathers in the upper reaches and drifts through the beam of a caving lamp like low cloud.
Er Wang Dong is vast in its own right, with more than 42 km of surveyed passage, a maximum depth of 441 m and two great collapse shafts, the Niubizi and Qingkou tiankengs, dropping in from the surface above. The Hong Meigui Cave Exploration Society carried out much of the exploration here, and photographs taken in the chamber for National Geographic brought it to a wide audience. There is no tourist access: the hall is reached on multi-day caving trips that carry everything in and out.
9. Hong Meigui Chamber
Hong Meigui Chamber measures 54,870 m², which places it ninth by floor area — though its margin over the chamber below is so slight that the two are effectively tied. It takes its name from the Hong Meigui Cave Exploration Society, the group behind much of the exploration of southern China's karst, and it was among the chambers laser-scanned during the 2013 China Caves campaign, with the results presented at the Hidden Earth conference the following year.
What the scans captured was a chamber whose roof arches close to 290 m above a floor of mud and collapsed rock, proportions that make it far taller than it is broad. Like the other Chinese chambers on this list it is a working expedition site rather than a visitor attraction, with no lighting, no path and no ticket office. Almost everyone who has stood in it is either a caver or one of the photographers who travel with them.
10. Titan Chamber
Titan Chamber covers 54,750 m² — just 120 m² less than Hong Meigui Chamber above it, a gap of around two parts in a thousand and comfortably inside the margin of error of any cave survey. The two are best read as joint ninth. Titan lies in the karst of southern Guizhou province in China, and was measured during the same laser-scanning campaign that fixed the dimensions of Miao Room and Hong Meigui Chamber.
That campaign changed how the world's biggest chambers are ranked. Before 3-D scanners went underground, chamber sizes were worked out from tape, compass and estimated roof heights, and the results were often far too generous — Sarawak Chamber's published volume fell by more than a third once it was scanned properly. Titan is one of the relatively few voids on Earth whose size rests on measured data rather than an educated guess, and like its neighbours it is reached only by expedition.
11. Belize Chamber
The Belize Chamber takes up about 49,000 m², running roughly 300 m long by 150 m wide with a ceiling some 65 m overhead — widely reckoned the largest cave room in the Western Hemisphere, and the only entry on this list from anywhere in the Americas. It sits inside Actun Tun Kul, one of four caves making up the Chiquibul Cave System in the Cayo District of western Belize, the largest and longest cave system in Central America with around 65 km of mapped passage running beneath the forest towards the Guatemalan border.
A second great room, the Chiquibul Chamber, lies in the same system. Chiquibul is protected within a national park and forest reserve, and its caves have been a focus of conservation work for decades, with management plans allowing only very limited and closely controlled tourism. The system carries a substantial underground river and holds Maya archaeological material, both of which argue for keeping visitor numbers low. In practice access goes to researchers and organised expeditions rather than independent travellers, and the journey in crosses some of the most remote forest in the country.
12. Salle Tuke
Salle Tuke closes the list at 48,000 m², a chamber about 240 m long, 200 m wide and 180 m high holding some 6.24 million m³ of space. It lies within the Minyé cave system in the Nakanai Mountains of New Britain, Papua New Guinea, and takes its name from the village of Tuke on the plateau above. The Minyé doline leading into it is a spectacle in its own right — a near-circular shaft roughly 350 m across and between 400 and 510 m deep.
A powerful underground river runs through the chamber, discharging between 15 and 25 m³ of water every second, and the Nakanai Mountains catch some of the heaviest rainfall on Earth — the engine that carved all of this out of the limestone. French-led expeditions have been exploring the system since the 1980s. Getting there involves a helicopter or a multi-day trek through rainforest with local guides, which leaves Salle Tuke among the least visited great chambers anywhere.
FAQ: The World's Biggest Cave Chambers
What is the biggest cave chamber in the world?
Sarawak Chamber in Malaysian Borneo is the largest cave chamber on Earth by floor area, covering 154,530 m² inside Gunung Mulu National Park — the record Guinness World Records certifies. By volume the title goes instead to China's Miao Room, which encloses about 10.78 million m³ despite covering less ground.
Which is bigger, Sarawak Chamber or Miao Room?
It depends which measurement you use. Sarawak Chamber covers more floor, 154,530 m² against Miao Room's 140,540 m². Miao Room is narrower but far taller, so it holds more air — roughly 10.78 million m³ to Sarawak's 9.58 million. Both records are genuine; they simply measure different things.
Can you visit the world's biggest cave chambers?
Very few of them. Most lie at the end of expedition-grade caving trips with no lighting, paths or handrails, and Oman's Majlis al Jinn has been off limits to visitors since 2008. Benua Cave in Bougainville is the most approachable, though reaching it still means a guided walk through remote country.
How are cave chambers measured?
Surveyors map the outline of the floor and the height of the roof, then work out area and volume from those figures. Since around 2010 the largest chambers have been scanned with 3-D lasers, which proved far more accurate — older tape-and-compass estimates often overstated a chamber's size considerably.
Which country has the most giant cave chambers?
China, with four of the twelve: Miao Room, Cloud Ladder Hall, Hong Meigui Chamber and Titan Chamber, all in the karst country of the south. Papua New Guinea contributes two. Eight countries appear in total, and Belize is the only one from anywhere in the Americas.
Planning more of your trip? Keep exploring more world record-breakers.