In the latter half of the 19th century, the West had been won. The frontier was closed, and America was feeling panicked about its identity. Who were we if not the gunslinging pioneers of the Wild West? Were we soon to be soft-bellied city-slickers? Not if Teddy Roosevelt had anything to say about it. Once the cowboy president was in office, he signed the Antiquities Act, which gave commanders in chief the ability to designate national monuments. Over the years swaths of land were set aside for protection, but in 1916 Congress solidified the movement by founding the National Park Service. On hundred years and about 400 parks later, the National Park Service is still going strong.

The National Parks are intended to be a living “textbook” to America’s history. They were here long before the United States of America, and are, as historian Wallace Stegner put it, “Absolutely American, absolutely democratic, they reflect us at our best rather than at our worst.” We forget sometimes how big the country is, but the fact that the Everglades and Joshua Tree fall under the same administration serves as a helpful reminder how vast and varied the States are.

The Grand Canyon and Old Faithful are certainly not to be missed. But national parks are huge! In addition to the classic sights, there are a million hidden wonders just waiting to be found, from ancient artifacts to clandestine caves. In celebration of the National Park Service’s 100th birthday, admission to any national park is free between August 25th and 28th, so no better occasion to spend some time reveling in the natural wonders the U.S. has to offer.

To aid your exploration, here is a list of places in the Atlas that are hidden tucked away within National Parks and National Forests. Get out there and find them.

1. Havasupai Falls


The hidden waters of Havasupai Falls. (Photo: John Roig/CC BY 2.0)

Havasupai Falls are a well-kept secret of the Native American tribe they are named after and owned by. Understandably reluctant to open the falls to throngs of tourists, the Havasupai people issue a few camping permits a year to would-be visitors. If you’re one of the applicants lucky enough to receive one of the permits, your choices of reaching the falls are by helicopter, mule, or 10-mile hike. The Havasupai Falls are colored a shocking turquoise blue by the high levels of calcium carbonate in the water, which gives both the waterfall and the tribe their name: Havasupai roughly translates to “people of the blue-green waters.”

2. Silent Heroes of the Cold War National Memorial


The USAF 9068 propellor, surrounded by 14 stones

The propeller, salvaged from the mysterious airplane wreck, surrounded by 14 commemorative stones. (Photo: Atlas Obscura user kurtregner)

Early on November 17, 1955 an Air Force DC-4 plane carrying 10 CIA scientists and 4 flight crew members took off from Burbank, California and headed to Area 51. It never arrived—the flight was reported missing a mere hour later. The plane had crashed at the peak of Mt. Charleston, killing all of its passengers. All of this information—from the flight itself, to the crash, to the identity of every person involved—was classified for 40 years. It was only once Boy Scout leader Steve Ririe had stumbled upon the wreckage and made it his mission to find out what happened that the details of the crash were released. Still, we don’t know the reason for the flight or why it crashed. Today, the propeller of the DC-4 is part of the Silent Heroes of the Cold War Memorial, the only National Memorial of its kind. It is dedicated to the anonymous individuals who lost their lives under Cold War’s blanket of secrecy.

3. Ptarmigan Tunnel


Ptarmigan Tunnel

The entrance to diminutive Ptarmigan Tunnel. (Photo: Atlas Obscura user cbrents)

Nestled amidst the rugged mountain landscape of Glacier National Park is an enforced tunnel, which looks like it might have been dug by dwarves for some kind of ancient fortress. In actuality, Ptarmigan Tunnel is just a small, human-made structure, but its existence allows for some incredible views of Glacier National Park. The tunnel was dug in 1930 with two jackhammers on either side of the rock wall and a healthy amount of dynamite. Though the tunnel is completely unlit and just a little bit creepy, passing through it saves hikers the treacherous trip over the wall from Many Glacier to Belly River Valley.

4. Aerojet Dade Rocket Facility


The SL-3 Rocket before it was covered.

The abandoned rocket, viewed through a tiny hole in its cover. (Photo: Brett Levin/CC BY 2.0)

In the fervor of the Space Race, NASA began to experiment with different methods of fueling the mechanical behemoths that were to shuttle mankind into space. The Aerojet testing grounds were deep in the swampy Everglades, easily hidden from the Soviets. NASA ended up using a different kind of fuel than what Aerojet was testing, and the facility was abandoned. But when you’ve got a failed secret rocket in a hole in a national park, it’s difficult to find someone to take it off your hands. No attempts to repurpose the land ever took off, and so the facility, rocket and all, remains as secluded and abandoned as ever.

5. Welch Springs Hospital Ruins


Welch Springs Ruins

Welch Spring Hospital ruins. (Photo: National Park Service/Public Domain)

In the early years of the 20th century, it was thought that fresh air and spring water could be cures for consumption (aka tuberculosis). Dr. C.H. Diehl opened the Welch Spring Hospital on these grounds after purchasing the land for just $800. It wasn’t the pseudoscience that caused the hospital to close its doors for good, but its inaccessible location. Sick people had trouble making the hike through the Ozarks, and when the doctor died in 1940 his buildings were left to nature.

6. Tri-State Peak


Concrete lines mark out the corners of Tennessee, Kentucky, and Virginia. (Photo: Atlas Obscura user sheepdontswim)

They say you can’t be two places at once, but Tri-State Peak begs to differ. Here, you can be three places at once: the great states of Tennessee, Kentucky, and Virginia. This site, which is nondescript enough that it might be overlooked, is also the beginning of the trail forged by folkloric frontiersman Daniel Boone.

7. Prometheus Tree Stump


Prometheus Tree Stump

What remains of the Prometheus Tree. (Photo: Jrbouldin/Public Domain)

When Donald R. Currey was just a graduate student, he made the biggest mistake he possibly could have. He was researching the Little Ice Age by taking samples from ancient trees, and had zeroed in on a grove of bristlecone pines in Nevada. After accidentally jamming his boring tool into a tree he estimated to be about 3,000 years old, Currey convinced the Forest Service to let him cut it down to date it. After felling it, he realized it was much older than he thought. In fact, it was much older than anything—the tree, named Prometheus, had been growing for upwards of 5,000 years, and was the oldest ever dated. Its stump, which measures eight feet across, still sits in the pine grove.

8. McKittrick Canyon


Some Fall Color in McKittrick Canyon

A pocket of abundant fall foliage in the middle of an arid desert. (Photo: Fredlyfish4/CC BY-SA 3.0)

Guadalupe Mountains National Park is in west Texas, where dry dusty desert stretches for miles. But McKittrick Canyon is a lush oasis in the middle of it all. Protection from the surrounding mountains make it a perfect little pocket of flora. Here, desert plants like yucca and cacti flourish, but so do unexpected ones like ash and maple trees, as well as an abundance of wildflowers. It may be hard to get to, but the canyon is far from undiscovered. Archaeological finds indicate people lived in “the prettiest spot in Texas” as long as 12,000 years ago.

9. Wreck of the E.C. Waters


Preserving the wreck of the steamboat. (Photo: Atlas Obscura user Martin)

Capitalist E.C. Waters wanted to make a profit off of the growing popularity of Yellowstone, the first national park, and he did so ferrying passengers across the lake with a series of steamboats. This might have worked out okay, except for the fact that Waters was not a nice man. He vandalized a geyser, infuriated customers, and opened a game show and zoo that landed him with allegations of animal abuse (in the late 19th century, so you know it had to be bad). To top it all off, in 1906 Waters hired his biggest boat of all and named it after himself. Park officials were over his bad behavior though, and by the very next year a sign was posted that read “E.C. Waters… having rendered himself obnoxious during the season of 1907, is… debarred from the park and will not be allowed to return.” E.C. Waters (the boat) was left to languish in the lake, where its rotting hull still sits.

10. Skunk Ape Research Headquarters



A promotional sign/warning outside the preserve. (Photo: John Mosbaugh/CC BY 2.0)

You could call the Skunk Ape (Big Foot’s stinkier cousin) Dave Shealy’s white whale. Despite the fact that the National Parks System dismisses the Ape as a “local myth”, Shealy asserts there are between seven and nine living in the park and has made it his life’s work to find them. He doesn’t want to poach the cryptids though—he loves the Skunk Ape, and in teaching about it he has raised awareness about the Everglades’ ecosystem. His headquarters, situated on a campsite in the park, contain educational artifacts like footprint casts and ape droppings as well as souvenirs.

11. Humphreys Peak B-24 Wreckage


Humphreys Peak B-24 Wreckage

Remnants of the ill-fated B-24. (Photo: Atlas Obscura user zards)

Near Humphrey’s Peak (the highest point of elevation in Arizona), the scattered metal remains of an Air Force B-24 lie among the rocks. The plane crashed in 1944, tragically killing all eight of the men aboard. The location of the crash is very difficult to access, hence why pieces of the aircraft remain on Humphrey’s Peak rather than a monument. Advanced hikers may attempt to find the wreckage, but for the less adventurous of us, the glinting metal atop the peak can apparently be seen from parking lot on sunny days.

12. Sliding Rock


Sliding Rock

Sliding Rock is nature’s Slip ‘n Slide. (Photo: Jared/CC BY 2.0)

Take a ride down a waterfall on a gently sloping rock, smoothed by eons of water, into a natural basin. It’s as though nature intended for you to have fun. This is actually one of the less-hidden spots on this list—Sliding Rock is growing more crowded, and apparently even has its own lifeguards now.

13. Rush Ghost Town


Rush Ghost Town

The remains of Rush are kept up by the parks service. (Photo: Atlas Obscura user scoobysleuth)

Rush used to be the second largest city in Arkansas. It thrived off profitable zinc mining, but when that industry dried up so did the town, and Rush was declared officially abandoned in 1972. Because the town’s buildings and mines were left within the bounds of a national park, the Park Service elected to preserve them as a historical resource. Some of the structures date back as far as the 1880s, and little has been changed.

14. Hall of Mosses


Hall of Mosses.

Moss, moss, and more moss. (Photo: Kgrr/CC BY 3.0)

This verdant trail in Olympic National Forest looks like something out of a fairytale. The Hall of Mosses is located within the Hoh Rainforest, which (as you might expect) gets a lot of rain. Fourteen-plus feet of precipitation per year cause the trees to grow stunted root systems, which in turn causes them to fall more easily. Moss quickly grows over the graveyard of trees. Walking this path is much like exploring ancient ruins. It’s magical, otherworldly, and very old.

15. Holzwarth Trout Lodge


Inside the Holzwarth Historic Site kitchen, preserved in its original state.

The kitchen of the Holzwarth dude ranch, preserved in its original state. (Photo: daveynin/CC BY 2.0)

When the Holzwarth family emigrated from Germany to Colorado, they sustained themselves by ranching. Their homestead on the Colorado River was a pristine site, with views of the surrounding mountains, and it attracted guests almost from the moment they moved in. They expanded, turning their home into a trout lodge and bed and breakfast-style ranch. The lodge remained open until 1974, when, upon purchasing the land from the Holzwarths, the National Park Service razed several buildings. However, the original lodge was left standing as a historic site, and now visitors can see exactly what it was like to live on the Colorado River in the early 20th century.

16. Coconino Lava River Cave


Inside the lava river cave.

The walls of the caves were smoothed by the lava that shaped them. (Photo: Coconino National Forest/Public Domain)

Lava hardens from the outside in, meaning that as the parts that are exposed to the air form a hard shell, a river of lava still pumps through the center. This kind of volcanic activity leaves behind almost perfectly circular tubes, which appear manmade, but were formed of nature’s own accord. This is the case with the lava river caves in Coconino National Forest. Through an unremarkable hole in the ground one can enter into a winding maze of cave tunnels that intersect and loop around each other.

17. Pikes Peak Summit House


The original Summit House, built in 1873.

The original summit house, built in 1873. The gift shop and restaurant operate out of a newer building just feet away. (Photo: mark byzewski/CC BY 2.0)

Scaling Pikes Peak isn’t as difficult as it was for its first ascendant in 1820 (now you can go by car or rail), but the Summit House will be there to greet you no matter how hard your trek was. There are the predictable keychains and postcards available for purchase here, but the Summit House’s real selling point is its donuts. Because of the 14,115 foot altitude, water boils at a lower temperature, and food must be cooked differently. The Summit House has been frying its signature cake donuts with the same secret recipe since 1916. Some hikers claim the trip up the mountain is worth it for the pastries alone, but the view from Pikes Peak is pretty awe-inspiring as well.

It was this very vista that prompted Katharine Lee Bates to write “America the Beautiful” in 1893, just over two decades before the National Park Service was born.

Update, 8/25: This article mistakenly included National Forests as part of the Nationals Park Service. We have updated the article to note that National Forests are part of a different agency. We regret the error.