The title of “biggest cave” depends entirely on the metric used for measurement. While length, depth, and volume all contribute to a cave’s overall scale, scientists who study caves often use total internal volume to determine the largest single subterranean space. This focus on volume identifies the world’s most massive known cave passage. The sheer scale of these natural voids is difficult to comprehend, as the largest chambers can easily dwarf human-built structures.
The World’s Single Largest Cave Passage
The record for the largest known single cave passage by volume belongs to Hang Sơn Đoòng Cave, located in the Phong Nha-Kẻ Bàng National Park of Vietnam. A British-Vietnamese team first fully explored and surveyed this immense subterranean river valley in 2009. The main passage stretches for more than three miles, with sections reaching colossal scales.
The average width of the passage is approximately 490 feet, and its height can reach up to 660 feet. The cavern is large enough that a Boeing 747 airplane could fly through the passage without scraping its wingtips. Its estimated total volume is an astonishing 38.5 million cubic meters, making it five times larger than the previous volume record holder, Deer Cave in Malaysia. This enormous size resulted from the cave’s formation along a large fault line in ancient limestone, allowing for horizontal expansion. The cave also features two massive ceiling collapses, known as dolines, which allow sunlight to stream in and create unique underground ecosystems.
Defining Cave Size: Volume Versus Length
The ambiguity surrounding the “biggest cave” stems from the three distinct measurements used: volume, length, and depth. Volume, measured in cubic meters, calculates the total internal space, making it the preferred metric for determining the largest single chamber or passage. Measuring the volume of an irregular natural space is complex, often relying on detailed three-dimensional laser scanning and modeling.
Surveyed length is the total linear extent of all connected and mapped passages within a cave system. This measurement is generally more objective and easier to verify, which is why it is often cited when discussing the most extensive underground networks. Depth measures the vertical distance from the highest entrance to the lowest explored point. A cave may be incredibly deep, consisting of narrow, vertical shafts, but its total volume may be relatively small compared to a horizontally expansive system like Sơn Đoòng.
Other Record Holders in the Global Cave Network
While Hang Sơn Đoòng holds the record for the largest single passage by volume, the world’s longest cave system is Mammoth Cave in Kentucky, United States. This vast network of passages has been mapped to over 420 miles (676 kilometers), with explorers continually connecting new sections. Mammoth Cave, formed in the Mississippian-age limestone of the Pennyroyal Plateau, is established as the world’s most extensive interconnected system.
The record for the world’s deepest cave is currently held by Veryovkina Cave, located in the Arabika Massif of the Gagra mountain range in Abkhazia, Georgia. The confirmed depth of Veryovkina plunges to an astonishing 7,257 feet (2,212 meters). This deep cave consists of a series of tight, steep shafts, making its total volume significantly smaller than Sơn Đoòng, but its vertical scale is unmatched globally. The former deepest cave, Krubera Cave, is located nearby and reaches 7,208 feet (2,197 meters), underscoring the extreme depth of this karst area.