This lava tube is located in Gifford Pinchot National Forest to the south of Mount St. Helens in Washington. This popular hiking destination was discovered in 1951. The uniqueness of this cave is that the lava tubes are an unusual occurrence in this region.
Home to 400,000 bats, including the Mexican free-tailed species, and pre-Jurassic fossils, Carlsbad Caves can be accessed via an elevator and lit walkway as well.
Formed almost 1.5 million years ago, these caves have stunning calcite crystal formations, which are perfect for spelunking.
This limestone cave is the warmest cave, at a constant 62 degrees year-round. Formations include stalactites, stalagmites, flowstone, cave popcorn, cave bacon, soda straws, and helictites.
This extensive cave system is located in between Sweetwater and Madisonville. It is best known for having the country’s largest and the world's second largest non-subglacial underground lake -- the Lost Sea.
The largest known cave in Alaska, the entrance faces the shallow El Capitan Passage. This cave has a variety of wildlife like river otters, two species of brown bats, and cave-adapted organisms such as amphipods, collembolans, and mites.
This cavern features two of the two deepest pits in the country -- Fantastic pit that has a depth of 586 feet, and Incredible pit that has a depth of 440 feet.
Fantastic Caverns is the only cave in the country to offer a complete ride-through tour. The caverns used to be a meeting place for the Ku Klux Klan and were then used as a speakeasy during Prohibition. The 1950s and 1960s saw the caverns playing host to music concerts.
A hundred and seventy miles of explored passages makes this the third-longest in the world. The guided tour allows you to spelunk and crawl covering nearly a mile of this underground system that is occupied by bats that reside here in winter.
Discovered in 1974, Kartchner Caverns State Park features a show cave with 2.4 miles (3.9 km) of passages. Carved out of limestone the caves are filled with speleothems that have been growing for more than 50,000 years.
Lechuguilla Cave is well-known for its geology, rare formations, and pristine condition. It holds a variety of rare speleothems, including sulfur deposits, gypsum chandeliers, hydromagnesite balloons, and cave pearls.
Located in the Great Basin National Park, these caves have passageways that are 2 miles long.
Discovered in 1878, Luray Caverns has columns, stalactites, stalagmites, and even mirrored pools. The caverns are best known for the Great Stalacpipe Organ.
Home to the endangered Kentucky cave shrimp, Mammoth Cave has signs of human habitation from 6000 years ago. Limestone strata capped by a layer of sandstone has made the cave system stable. It also has more than 400 miles of passageway.
Marvel Cave is a National Natural Landmark that was discovered by the Osage Indians in the early 16th century. While, there is evidence that the Spanish explored the cave back in 1541, the first recorded expedition was in 1869.
These caves have been formed as a result of millions of years of limestone deposits. One of the most visited caves in Missouri, pre-Columbian Native American artifacts have been found here.
This largest known commercial cavern is believed to reach depths of 230 feet. Of this only upto 180 feet below the surface is open to public. The cave was discovered in 1960.
As one of the largest caves in the Midwest, Niagara Cave is rated among the top 10 best caves. Its older-than-dinosaurs fossils in limestone, 18 m waterfall, and guided tour are some of its main attractions.
Discovered in 1874, these caves are located in the protected area in the northern Siskiyou Mountains of southwestern Oregon.
These caves are located at a cliff and are surrounded by pine forests. Formed during the last Ice Age, this cave system has nine caves.
This cave is best known for having the most complex and large honeycomb pattern of boxwork, a type of speleothem.
Spelunking, also known as cave diving, can be considered an “extreme sport”. With nearly 50,000 caves in the US alone, there is no dearth of small, tiny spaces for thrill seekers to squeeze into. If you’re looking to pick up a new hobby, try something extreme or simply satisfy your curiosity, here are 21 fantastic caves to begin with.