Wind Cave National Park

Wind Cave is named for the air that moves through its natural entrance, breathing in or out depending on the pressure outside, loudly enough that two brothers found it by the sound in 1881. More than two hundred kilometres of passage have been mapped inside a block of rock barely a couple of kilometres across, making it one of the densest cave systems known, and it holds well over ninety per cent of the world's discovered boxwork, thin honeycomb fins of calcite standing out from the walls in a lattice found almost nowhere else. Above ground the park protects a large stretch of mixed-grass prairie with bison, elk and pronghorn. The cave is a place of emergence in Lakota tradition.

What you actually see

• Boxwork - the honeycomb calcite lattice found almost nowhere else on earth.
• The natural entrance - the small hole that breathes audibly with the weather.
• The prairie above - bison, elk and pronghorn on mixed-grass grassland.
• The candlelight tour - a lit-by-candle route through undeveloped passage.

When to go

May to September has the full range of tours, including candlelight and wild caving; a reduced schedule runs the rest of the year. The cave holds around twelve degrees year-round, so bring a layer whatever the surface weather. Tours sell out on summer days, and same-day tickets go early.

Honest expectations

All cave access is by ranger-led tour with fixed times and limited numbers, so arrive early or expect to wait hours in summer. The passages are narrow with many stairs and are not step-free. Boxwork is subtle and photographs poorly in low light; visitors expecting the big stalactite chambers of Carlsbad will find a very different cave.

Nearby

Custer State Park is just north; Mount Rushmore and the Badlands are within two hours.