Underground Idaho: Peacocks, Prehistoric Artifacts, and Volcanic Wonders Await at Mammoth Cave

As temperatures climb and the school year winds down, families across the Magic Valley are beginning their hunt for the next great summer adventure. While many seek the peaks of the Sawtooths, one of the state's most eccentric and historic destinations lies beneath the surface.

Located eight miles north of Shoshone along Highway 75, Idaho’s Mammoth Cave offers a blend of natural wonder, Cold War history, and a museum collection so vast it has been dubbed the "Smithsonian of the Desert."

The Discovery of a "Diamond in the Rough"

The site’s modern history began in 1954 when a high school senior named Richard Olsen stumbled upon the cave opening while out hunting coyotes and bobcats. Olsen eventually homesteaded the land, spending the rest of his life transforming the volcanic site into a public treasure.

"Richard found the place... and we've been doing tours out here since the early 60s," said site manager Charles Drake. Olsen’s passion wasn't just for the cave, but for the world at large; he spent decades traveling the globe to bring artifacts, taxidermy, and curiosities back to his home in the Idaho desert.

Museums and "Peacock Security"

Before descending into the earth, visitors must navigate a sprawling complex that includes the Shoshone Bird Museum of Natural History and the Richard Arthur Olsen Museum. The exhibits feature:

• Prehistoric Artifacts: Ancient fossils and Stone Age tools.

• Global Taxidermy: A massive collection of birds and animals from every continent.

• Cultural Curiosities: Baskets, pottery, and relics spanning centuries.

Visitors should also keep an eye out for the property's 40 to 50 free-range peacocks. Far from just decorative, the birds serve a practical purpose. "They are really aggressive to rattlesnakes," Drake explained. "They make it a little safer out here, and they are really great at taking care of ticks."

The Mammoth Lava Tube

The main attraction is the cave itself—one of the largest volcanic tubes in the world open to the general public.

• Self-Guided Exploration: Visitors are handed a lantern and allowed to walk the quarter-mile path at their own pace.

• Constant Temperatures: The cave remains a crisp 42°F year-round, making it a perfect escape from the summer heat.

• Cold War History: During the 1960s, the cave was officially designated as a civil defense fallout shelter, stocked with enough food and water to sustain 8,000 people in the event of a nuclear emergency.

While the "fallout shelter" signage still hangs at the entrance, Drake admits the cave's role has changed with the times. "It could still provide shelter for a lot of things... but nuclear holocaust? Probably not."

Mammoth Cave and the museums are open seven days a week from 10 a.m. to 6 p.m. Whether you come for the prehistoric bones or the subterranean chill, it remains one of the most uniquely "Idaho" stops on the map.

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