Geological & Natural
Canyons, geysers, and forests whose significance predates human record — the landscapes that shaped where and how America was settled.
Six landmarks across 5 states. Start with Mammoth Cave, Devils Tower and Old Faithful.
- Landmarks
- 6
- Period
- Deep time
Pictured Mammoth Cave
Daniel Schwen · CC BY-SA · via Wikimedia Commons
The Landmarks
- Geological & Natural
Mammoth Cave
Mammoth Cave, KY
Beneath the rolling hills of central Kentucky lies the longest cave system ever discovered on Earth — more than 420 mapped miles of passages, and still growing as explorers connect new sections.
Geological & NaturalDevils Tower
Devils Tower, WY
America's first National Monument, and sacred ground to Plains nations centuries before that designation, Devils Tower's improbable columned silhouette has drawn climbers, ceremonies, and — thanks to Hollywood — UFO seekers.
Geological & NaturalOld Faithful
Yellowstone National Park, WY
The geyser whose reliable eruptions helped convince a skeptical Congress that Yellowstone's wonders were real, kickstarting the entire American national park idea.
Geological & NaturalCarlsbad Caverns
Carlsbad, NM
A cave system first noticed because of the bats pouring out of it, explored by a persistent cowboy with a homemade ladder, and now home to one of the largest single cave chambers in North America.
Geological & NaturalCuster State Park
Custer, SD
Named for the officer whose 1874 expedition broke a treaty and triggered a gold rush into land promised to the Lakota, Custer State Park today protects one of the largest public bison herds in the world across some of the most dramatic terrain in the Black Hills.
Geological & NaturalMuir Woods National Monument
Mill Valley, CA
One of the last stands of old-growth redwoods near San Francisco, saved from a water company's dam by a conservationist who then declined to have the grove named after himself, insisting it honor John Muir instead.