Terrain: tremendous variation of terrain on each of the continents; check the World 'Elevation' entry for a compilation of terrain extremes; the world's ocean floors are marked by mid-ocean ridges while the ocean surfaces form a dynamic, continuously changing environment; check the 'Terrain' field and its 'major surface currents' and 'ocean zones' subfields under each of the five ocean (Arctic, Atlantic, Indian, Pacific, and Southern) entries for further information on oceanic environs
Ten Cave Superlatives: compiled from "Geography - note(s)" under various country entries where more details may be found
largest cave: Son Doong in Phong Nha-Ke Bang National Park, Vietnam is the world's largest cave (greatest cross sectional area) and is the largest known cave passage in the world by volume; it currently measures a total of 38.5 million cu m (about 1.35 billion cu ft); it connects to Thung cave (but not yet officially); when recognized, it will add an additional 1.6 million cu m in volume
largest ice cave: the Eisriesenwelt (Ice Giants World) inside the Hochkogel mountain near Werfen, Austria is the world's largest and longest ice cave system at 42 km (26 mi)
longest cave: Mammoth Cave, in west-central Kentucky, is the world's longest known cave system with more than 650 km (405 mi) of surveyed passageways
longest salt cave: the Malham Cave in Mount Sodom in Israel is the world's longest salt cave at 10 km (6 mi); its survey is not complete and its length will undoubtedly increase
longest underwater cave: the Sac Actun cave system in Mexico at 348 km (216 mi) is the longest underwater cave in the world and the second longest cave worldwide
longest lava tube cave: Kazumura Cave on the island of Hawaii is the world's longest and deepest lava tube cave; it has been surveyed at 66 km (41 mi) long and 1,102 m (3,614 ft) deep
deepest cave: Veryovkina Cave in the Caucasus country of Georgia is the world's deepest cave, plunging down 2,212 m (7,257 ft)
deepest underwater cave: the Hranice Abyss in Czechia is the world's deepest surveyed underwater cave at 404 m (1,325 ft); its survey is not complete and it could end up being some 800-1,200 m deep
largest cave chamber: the Miao Room in the Gebihe cave system at China's Ziyun Getu He Chuandong National Park encloses some 10.78 million cu m (380.7 million cu ft) of volume
largest bat cave: Bracken Cave outside of San Antonio, Texas is the world's largest bat cave; it is the summer home to the largest colony of bats in the world; an estimated 20 million Mexican free-tailed bats roost in the cave from March to October making it the world's largest known concentration of mammals
Definition: This entry contains a brief description of the topography.
Source: CIA World Factbook - This page was last updated on Saturday, September 18, 2021
