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.
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.
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.
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.
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.