Caves are typically associated with primitive people – however, they are important in today's society for reasons of tourism and biodiversity. The longest cave in the world is the Mammoth Cave, which measures 405 miles in length and is found in Kentucky, United States. Here are some other amazing caves.
Longest Caves in the World
By far, the longest cave in the world is the Mammoth Cave in Brownsville, Kentucky, US. This cave is a staggering 405 miles in length. Mammoth Cave is located in a National Park and visitors can tour the inside. Long ago, Native Americans used some areas of the cave as burial sites. The interior is home to several species of bats, some of which (such as the Eastern Small-footed bat) have gone down in numbers. The park is currently taking on conservation efforts.
Sistema Sac Actun-Dos Ojos
The second longest cave in the world is the Sistema Sac Actun and Dos Ojos in Quintana Roo, Mexico. These cave systems are underwater and run along the Caribbean shore and have two types of tunnels running through it. The tunnels run parallel and perpendicular to the coastline. Tourists can snorkel and scuba dive in some areas of the caves.
Number 3 on the list is the 180-mile long Jewel Cave located in Custer in South Dakota, US. This cave was discovered in 1900 when two men felt a cool air escaping through a small hole in the ground. They widened the hole and found a cavern filled with calcite crystals, hence the name. Of the many formations inside, the rarest is a hydromagnesite balloon which is formed when gas fills the substance caused by precipitation of the mineral magnesium carbonate hydroxide.
Other Long Caves
Those caves listed above are the top 3 longest in the world. There are many more worth mentioning, all over 100 miles long. They are located all over the world and include Sistema Ox Bel Ha in Tulum, Quintana Roo, Mexico at 159.75 miles long, Optymistychna Cave in Korolivka, Ukraine (146.64 miles), Wind Cave in Hot Springs, South Dakota, US (142.72 miles), Lechuguilla Cave in Carlsbad, New Mexico, US (138.31 miles), Clearwater Cave in Miri, Sarawak, Malaysia (133.78 miles), Fisher Ridge Cave System in Brownsville, Kentucky, US (124.58 miles), and Hölloch in Muotathal, Switzerland (124.52 miles).
Different Types of Caves
There are 8 principle types of caves and they each have distinct formation processes. The first type is the solutional cave, which is formed by naturally acidic groundwater slowly eating away at rock, these cracks gradually expand over time. The second type of cave is the primary cave which is created by lava flows. Sea caves are located on coastlines all over the world and have been formed by waves cutting into the sea cliffs. The next common cave type is the erosional cave which, as the name suggests, are formed by erosion of either wind or water. Glacier caves have formed by melting and slow moving ice. Fracture caves are formed when layers of soluble rock dissolve between layers of less soluble rock. Talus caves are less akin to traditional caves, and are a kind of caves within unstable rock piles that are typically found at the bottom of cliffs. Finally, anchialine caves are found on coastlines and contain a mix of salt and freshwater.