Mammoth Cave: the longest known cave system in the world

Beneath the wooded hills of Kentucky lies the longest known cave system in the world. Cavers have mapped nearly 700 km of it, on five levels, and they discover more every year. Nobody knows where it ends.

History and origins

Here the limestone is capped by a layer of sandstone, which is impermeable. It has protected the passages from collapse for millions of years, while the underground rivers cut ever deeper.

Native Americans were already exploring the cave 4,000 years ago, by the light of cane torches. In the 19th century it became one of the country’s first tourist attractions. Its best guides were enslaved men. The most famous, Stephen Bishop, explored and mapped kilometres of unknown passages, and named chambers that are still visited today. The park was created in 1941, and it’s a World Heritage Site.

What to do there

• The Historic Tour: two hours through the natural entrance, in the great passages once mined for saltpetre. You go through a corridor so narrow that it’s called “Fat Man’s Misery”.
• The decorated chambers: the cave has few formations, because it’s dry. You mostly see them in a separate section, around a stone cascade called Frozen Niagara.
• The great domes: vertical shafts dozens of metres high, carved by seeping water.
• Lantern tours: as in the 19th century, with no electric lighting.
• Caving: a six-hour trip of crawling and squeezing through, with helmet and kneepads. You have to book, and not be too broad in the shoulders.
• Above ground: forest trails and the Green River, which you can canoe down. A small cable ferry takes cars across.

Stories and good to know

• In the 1840s, a doctor housed tuberculosis patients in the cave, thinking the air would do them good. The experiment was cut short. The stone huts are still there.
• The park is on Central Time, an hour behind Louisville. Check the time of your tour.
• Blind, colourless fish and crayfish live in the underground rivers.

Practical information for your road trip

• Getting there: the park is 1 hr 30 from both Nashville and Louisville, near Interstate 65.
• On site: a hotel, a restaurant and a shop next to the visitor center.
• Where to stay: at the park lodge, or in Cave City, 15 minutes away.
• Combine it with: Nashville and the Bourbon Trail, around Louisville.