The appropriately named Mammoth Cave near Brownsville, Kentucky, is the longest cave system in the world, with 412 miles of wondrous limestone and sandstone formations.
From Kentucky to New Mexico, our next stop is at the Carlsbad Caverns in Eddy County, New Mexico, near the border with Texas.
Another famous cave is Jewel Cave near Custer in South Dakota, which ranks third in the list of longest caves in the world.
Situated in southeastern Minnesota, Niagara Cave is a naturally formed cave that boasts an array of unique features.
The rich history of the Meramec Caverns alone designates it as one of the best caverns in the USA.
The Luray Caverns is undoubtedly one of the best caves and caverns in the USA due to their ornate natural decorations.
Ruby Falls in Chattanooga, Tennessee may have a romantic history in that it was named after the man's wife.
If you've grown disenchanted with the show caves that have dominated the list so far, Ape Cave near Cougar, Washington, offers some of the best spelunking in America.
Although Moaning Cavern has been visited by people for thousands of years, it was rediscovered by gold prospectors in the mid-19th century.