The most spectacular hidden natural wonders in the U.S.

Shoshone Falls was one of the first tourist destinations west of the Mississippi (even emigrants along the Oregon Trail would veer off track just to visit it). But these days, very few people outside of Idaho have ever even heard of “The Niagara of the West,” a 212-foot tall, 900-foot-wide cascade outside of Twin Falls. Despite its lack of notoriety, the waterfall, which flows over a vertical horseshoe-shaped cliff in the Snake River, is one of the country’s tallest, a full 45-feet taller than New York’s Niagara Falls. The best time to see Shoshone Falls is in the spring, when the river is bloated with snowmelt from the Rocky Mountains and, unlike visiting the actual Niagara Falls, you’ll be one of just a handful of tourists standing on its edge.

The haunting Bisti Badlands/De-Na-Zin Wilderness rises out of the ancient landscape of the Navajo Nation. The area was once a river delta at the edge of the primordial sea (it covered much of New Mexico around 70 million years ago), but once the water receded it left behind a 1,400-foot layer of sandstone, mudstone, shale, and coal. Over the millennia, melting glaciers, wind, and water have carved the rock into hoodoos, tabletops, mushrooms, and dozens of other whimsical shapes. A nesting place for golden eagles today, the high-desert badlands once harbored an ancestral raptor of a different sort: the Bisti Beast, the remains of a 30-foot tall Tyrannosaurus rex, were discovered here in 1997.

This unusual rock formation juts out of the shallow waters of Lake Huron at the tip of Michigan’s thumb. Over the centuries, the waves of the Great Lake have shaped the stone “stack,” slowly chiseling away the base while leaving the “turnip’s” top untouched while a tiny forest ecosystem grows on its crown. Although Turnip Rock is on private property, it can be seen by kayak or canoe via a seven-mile out-and-back paddle from the township of Pointe Aux Barques.

The crop of perfectly spherical boulders strewn across Northern California’s Bowling Ball Beach (one of the best secret beaches in the U.S.) were conceived over millennia of geological and hydrological activity. The concretions from which they’re formed— compact masses of rock and minerals—have been shaped by the ocean waves into dozens of knee-high orbs fit for a giant’s bowling alley. Located a few miles south of the town of Point Arena, the coastal oddity is best seen at low tide, when the stones emerge fully from the crashing waves.

A prehistoric spring fed by an underground river sits in the Florida karst outside Gainesville. Above it, a hole in the limestone lets sunlight pour in and releases steam from the 72 degree pool below. They call the cave the Devil’s Den and, since being purchased by private owners in the early 1990s, its 54-foot deep spring has become one of the most unique spots in the country to scuba dive and snorkel. Just two miles down the road is the Blue Grotto, a second karstic spring fed by the same underground river; with a fully exposed surface, it welcomes scuba divers to explore its depths 100 feet below.

The Wheeler Geologic Area was once designated as Colorado’s first national monument. But when the site was demoted to national forestland in 1950, its incredible landscape fell off the tourist map into relative obscurity. The 25-million-year-old volcanic ash spires and hoodoos marking the 60-acre geological area, however, are just as spectacular as they were when visitors were more frequent. The towering rock formations, which blossom from one of the largest volcanic eruptions the Earth has ever known, continue to be shaped by wind, rain, and snow into ever more precise shapes across the mountainside. While a rough, 14-mile four wheel drive-only road will take you straight to them, the seven mile hike along the East Bellows Creek Trail or Wason-Wheeler Trail will be much more rewarding.

The Apostle Islands sea caves, located in the Ojibwe homeland, are ancient formations shaped by water and ice. At Devils Island, Sand Island, and along the western boundary of Lake Superior, the elements have carved delicate arches, catacombs, and vaulted chambers from the red sandstone. In the summer, these caves are colorful and tranquil but in the frigid Wisconsin winter, they transform into magical ballrooms hung with sparkling curtains of ice. It’s the only time of the year that the caves can be reached by foot (in warmer months, you’ll still need a kayak to explore their inner reaches).

The bizarrely named Johnson’s Shut-Ins State Park in the Missouri Ozarks earned the moniker for its collection of pools or “shut-ins” bound and bordered by erosion-resistant igneous rock. As the East Fork of the Black River flows over the boulders and collects between them, it creates a sort of natural water park full of waterfalls, chutes, and potholes. The shut-ins range over 180 acres of the river and, while they can be seen from an observation deck above, it’s a whole lot more exciting just to jump right in.

Thor’s Well, a sinkhole in the rocky outcroppings of the Oregon coast, spends its days swallowing the ocean then spitting it back out again. The phenomenon, which some refer to as the drainpipe of the Pacific, likely began as a natural sea cave that, upon collapsing, broke open holes in its surface and base that inhale and exhale the water. Although it’s only 20-feet deep, the well is powerful: at high tide, it ejects the sea with a violent shudder, shooting the spray 40 feet into the air. A second “ocean geyser” a few hundred feet away, dubbed the Spouting Horn, also puts on a similar show without Thor’s drain-like funneling.

It wasn’t until 2017 that hydrologists solved the mystery of Devil’s Kettle Falls near Grand Marais, Minnesota. While the anomalous cascade’s east side drops 50 feet down a black rhyolite cliff into a pool below, the west side simply disappears into a hole in the rock. Objects thrown into the cataract disappeared too, with no explanation for where they went. There were all kinds of theories as to what actually happened to the water falling into the rock, but scientists now believe the most likely explanation is that the west side flows into an underground stream that rejoins the Brule River from underneath. You can see it for yourself on a 2.5-mile round trip hike through Judge C.R. Magney State Park, which leads to the waterfall’s overlook.

When a volcano erupts, the lava that flows from its core forms channels that, by cooling from the outside in, leave the molten liquid flowing within a hard exterior shell. When the lava on the inside finally solidifies—weeks or months or even years later—a long cave shaped like a colossal worm, otherwise known as a lava tube, is left behind. Most lava tubes are fairly short but Ape Cave, located in the Gifford Pinchot National Forest near Mount St. Helens in Washington, ranks in at 2.5 miles—it’s the third longest lava tube in North America. While the lower 3/4-mile long cave route is family-friendly, the upper route requires scrambling over breakdown and climbing up an eight foot wall in the eerie darkness.

The painted cliffs of Georgia’s “Little Grand Canyon” are an eye-catching example of human-induced erosion on a natural landscape. Farming operations in the 19th century broke down the loamy sediments in this southwestern section of the state, leaving behind an alternating pattern of deep gullies and towering red and white bluffs, mimicking a geological signature more commonly associated with the American Southwest. The canyon is so out of place that it was even named one the state’s seven natural wonders. A trail along the rim offers a view of the geological features; other routes will take you down into its deepest crevices.