In October 2024, a small team of climbers carried a seismometer up a column of rock in the northeast corner of Wyoming and placed it on top 867 ft over the boulder field below.
For 21 hours, it recorded everything.
When the team at the University of Utah published the results in the spring of 2026, the rock stopped being what everyone thought it was.
You were probably taught that Devil’s Tower is a fixed thing.
The cooled plug left inside a dead volcano.
Solid rock done changing.
The most permanent landmark in Wyoming.
That’s not what the data showed.
Right now, as you watch this, the tower is in motion.
It rocks back and forth about once a second, swaying east and west, then north and south, then twisting on itself, whether there’s wind or not.
And the motion is just the newest crack in the old story.
The rock layers around its base lean the wrong direction.
Its official age slid back by almost 9 million years, and the update sat in a conference abstract that barely anyone noticed, and plenty of visitors still insist they’re staring at a giant tree stump turned to stone.
So, what is Devil’s Tower?
But what got me wasn’t the seismometer.
It was one flat line in a 1956 government report on the local geology about the direction the ground slopes.
Remember that line, it matters later.
I’m Ambrose Wild.
And here’s the irony sitting underneath this whole story.
The country put this rock on a pedestal decades before anyone could explain what it was.
On the 24th of September, 1906, Theodore Roosevelt signed it into history under a law passed that same year, the Antiquities Act.
Devil’s Tower became the first national monument America ever had.
Ahead of every canyon and cliff dwelling.
It was pulling crowds even before that.
On the 4th of July in 1893, about 800 people camped along the Bellforche River to watch two local men, William Rogers and Willard Ripley, climb a 350 ft ladder of wooden pegs they’d hammered into a crack on the southeast face.
Rogers, dressed as Uncle Sam, had a flag on top by noon, and Ripley told his wife there was nothing up there but a little soil and some sage brush.
Two years later, Bill’s wife, Lenny, climbed the same ladder and became the first woman to reach the summit.
Then, in 1977, Steven Spielberg built the climax of Close Encounters of the Third Kind around this rock, and the tower has belonged to that movie ever since.
A campground near its foot still screens the film on summer evenings with the real thing standing behind it.
In 2021, the monument logged 550,000 712 recreation visits, the most in its history.
And in 2024, it drew more than 540,000.
Ask those visitors what they’re seeing, and most give the same answer.
An old volcano or the guts of one left behind after the mountain eroded.
It’s on the postcards and in the school books.
That answer began as an early guess.
And somewhere along the way, the guess got promoted to a fact, but the postcard version gets smaller things wrong, too.
And the first one is visible from the trail.
People call the columns hexagons, six sides each, like a honeycomb.
When the US Geological Survey mapped the monument, the geologist Charles Robinson wrote that most of the columns are five-sided with some four and six-sided ones mixed in.
The bigger ones measure six to 8 ft across at the bottom and taper to about 4t near the top.
And the park services own page today says most are hexagonal with many pentagonal.
Two official sources, same rock, and they can’t agree on how many sides it has.
If a detail you can count from the trail gets rounded off, think about what could be hiding in the parts nobody gets to look at.
And yes, the tree.
Of all the ideas people share about this rock online, the petrified stump gets the most agreement.
It deserves a fair hearing because one of the old native names for this place is tree rock.
Here’s how wood really turns to stone.
Minerals seep into a buried log and replace it cell by cell.
And the wood structure survives the swap.
You can still count growth rings in petrified wood.
Now go to the top of the tower.
It’s nearly flat, roughly 180x 300 ft with grass, cactus, and sage brush over bare rock, and there isn’t a ring or a grain in sight.
Crack open a piece and you’ll find white feldspar crystals, commonly a/4 to half an inch across in a fine gray rock.
Crystals like that grow when molten rock cools slowly.
Wood can’t make them.
And the tower is about 800 ft wide at its base.
No tree has ever come close to that or grown in five-sided columns.
That summit has seen some strange visitors.
In October 1941, a parachutist named George Hopkins jumped onto it from a plane.
A publicity stunt the park service knew nothing about.
He hit the target.
The plan was to climb down a 1,000 ft rope dropped after him.
But the rope landed on the side of the tower, out of reach.
The Goodyear company offered a blimp and the Navy offered a helicopter.
Meanwhile, planes dropped him food, water, and warm clothes, and a climber named Jack Durrence eventually led seven others up to bring him down, while some seven zero zero zero visitors watched over those six days, nearly a week alone on that rock, and he never found anything that looked like wood either.
So, the stump idea collapses on the rock itself.
Still, it asks the right question.
Where did those columns come from?
For most of the 20th century, there was no clean answer because geologists couldn’t even agree on what sort of body they were looking at.
In 1888, Franklin Carpenter described it as the neck of a dead volcano.
In 1907, Nelson Dartton and Cleopasoh Hara called it the worn remnant of a lacalith, a mushroom-shaped mass of magma that bulged the rock above it into a dome without ever breaking out.
A third camp went with a stock, a small body of magma that cooled underground and was later uncovered.
Three labels for one rock.
The mappers should have been able to settle it.
They tried.
And this is the detail almost everyone skipped.
In 1956, the Geological Survey published Robinson’s report on the monument.
He walked the sandstone and siltstone beds around the tower and measured their angles.
Half a mile to a mile out, the beds dipped gently away from the tower, 2 to 5°, forming a broad dome.
That fits the textbook.
But within 2,000 to 3,000 ft of the tower, he wrote, “The beds mostly tilt 3 to 5° inward toward it, forming a shallow basin.”
I mean, think about that for a second.
If the tower were the core of a lacalith, rising magma should have lifted those beds and tipped them outward the way a sheet slides off a tent pole.
Right beside the tower, the ground does the reverse.
It sags in as if something underneath had dropped.
Robinson stayed cautious.
His conclusion was that the intrusion was never much wider than the tower’s base today and that a thousand ft or more down it joins a sill or lacalith type body.
Around that base lies the talis, an apron of broken columns that wraps all the way around with blocks up to 8 ft thick and 25 ft long.
And that rubble pile is too small to come from a far bigger mass ground down to this size.
It was a sober, defensible reading, but that inward tilt just sat there in the report for decades, measured, recorded, and unexplained.
Then in 2015, an explanation came from halfway around the world.
Procop Zavvada of the Czech Academy of Sciences and three colleagues laid it out in the journal Geosphere.
For years, they’d studied a hill in the Czech Republic called Borin, a rounder forested but made of the same unusual rock.
At Borin, rising magma had hit groundwater, flashed it to steam, and blown a crater into the surface, what volcanologists call a mar.
Thick, sticky lava then welled up into that crater, and long afterward, erosion stripped the surroundings and left the core standing.
So they tested Wyoming against Borin.
Columns grow at right angles to whatever surface is cooling them.
So their pattern is a map of the original shape.
And at Devil’s Tower, the columns spllay outward near the base before straightening higher up.
Tiny magnetic minerals locked in the rock tell you which way it was flowing.
And here they stand roughly upright near the base, but lie flat near the top.
The team pushed soft plaster laced with magnetic particles up through an upside down cone of sediment and ran a computer simulation of cooling rock and the results matched the tower.
Suddenly, the line from 1,956 made sense.
A funnel-shaped crater that slumps inward leaves the beds around it, tilting toward the center.
Their verdict was that Devil’s Tower is the remnant of a Kool-Aid or low lava dome sitting in a crater blasted out at the top of a Mar Dotream volcano.
That still didn’t close the case.
The park allows so little sampling on this sacred site that the team got just one new rock sample which they combined with measurements from more than 30 years earlier.
Bernard Hson of Western Washington University, who wasn’t involved, called the idea interesting and certainly very plausible, but not the end of the other explanations.
And the proof, the crater rim, the old ground surface, whatever once capped the top, is precisely what erosion removed.
The same process that uncovered the tower wiped out the evidence of its birth.
Keep that single rock sample in mind, by the way.
It’s a big part of why the newest study didn’t take any rock at all.
The age should at least be settled.
For decades, nearly every book said 40.5 million years based on a 1,961 study using potassium argon dating, which was good for its era.
Then in 2002, Janet Duke, Brad Singer, and Ed Dit reported something different at the Geological Society of America meeting.
Using argon argan dating, heating Sanadedine crystals with a laser step by step, they got 49.04 million years for Devil’s Tower, plus or minus 160,000.
The Missouri butes, a cluster of the same rock about three and a half miles northwest, came back at 49.24 million.
Here’s what makes that interesting.
The older method had put those two neighbors almost 9 million years apart.
41.6 million for the tower and 50.9 million for the butes.
The new dates put them at essentially the same moment, two pieces of one burst of magma.
The catch is that the 2002 work appeared as a meeting abstract rather than a full journal paper.
So the old and new figures kept turning up side by side for years.
The park service now just says the tower formed around 50 million years ago, 1 to 2 m underground, and that erosion started laying it bare 5 to 10 million years ago.
A few people point to that back and forth as proof that dating rocks is guesswork.
The history says something closer to the reverse.
Two methods disagreed and the more precise one won.
Now, the moment the columns actually cracked in 2018, a University of Liverpool team led by the volcanologist Yan Lavali squeezed cooling bassalt from Iceland’s Aaf Jalaja Jakul volcano in a press and watched it shrink and split.
That magma crystallizes at around 980° C, but the cracks didn’t open until it was roughly 90 to 140° cooler, about 840 to 890°.
In Lavali’s words, the answer is hot, but after it solidified.
To be fair to the evidence, that was bassalt.
And Devil’s Tower is fondolite pfery, a rare ignous rock that nobody has tested this way.
The lesson that transfers is that the rock was already solid when it broke and columns this big point to a huge still mass cooling slowly.
The park service says these columns saw hundreds of feet and reached 10 ft wide.
And how they sit against each other turns out to be exactly what the seismometer ended up measuring.
We’ll get there.
Geologists needed a century of fieldwork and lab experiments to explain those grooves.
The people who lived around this rock had an explanation long before and it came with a name.
The tower is sacred to plains nations including the Lakota, the Cheyenne, and the Kioa.
And a federal committee would later count more than 20 tribes with close ties to it.
The Lakota call it MO Tila, Bear Lodge, and on maps from 1857 to 1901, that’s usually the name you’ll see.
Other names include greyhorn but tree rock and the place where bears live.
The kioa and the lot both tell of girls chased by giant bears.
The girls prayed and the rock under them rose higher and higher while the bears dragged their claws down its flanks.
The girls were lifted into the sky as the stars of the pleaides and the claw marks stayed on the stone.
Look at those long vertical grooves again with that in mind.
You can see them from miles away.
And they were claw marks to the people living here long before anyone called them cooling cracks.
So how did Bear Lodge become Devil’s Tower?
In 1875, Colonel Richard Irving Dodge took an army expedition into the Black Hills country the Fort Laram Treaty of 1,868 had set aside for the Lakota.
Dodge wrote that the Indians called this place Bad God’s Tower, a name, in his words, adopted with proper modification.
The modification was his, and the new name spread from his writing onto the maps.
The Park Service suspects a bad translation that confused bear with bad god and notes that no other record links this place to bad gods or evil spirits.
Even the apostrophe disappeared.
The 1,96 proclamation wrote it as Devil’s Tower, and the Park Service thinks drafting it may be where the naming board’s rule against possessive apostrophes began.
What gets me is the contrast.
The rock’s origin is unsettled because the proof washed away.
The name is unsettled even though the paper trail is complete.
In November 2014, Arval looking horse, spiritual leader of the Lakota, Dakota, and Nakakota nations, formerly proposed restoring Bear Lodge.
The comment period ended in 2015, and nothing changed.
Wyoming’s senators Cynthia Lumis and John Baraso have pushed a bill to forbid any renaming, first in 2021 and again in January 2025.
And the naming board won’t move on a name while a related bill is pending.
Then in June 2024, the Advisory Committee on Reconciliation in Place names gathered in Rapid City, South Dakota, and urged the Interior Secretary to make it Bear Lodge, citing more than 20 tribes with close ties to the site who find the current name offensive.
Ogden Driskll, the Wyoming State Senator for the area, said Bear Lodge would be just as wrong.
On the 27th of February 2025, Interior Secretary Doug Bergam shut the committee down.
The sign at the gate still reads Devil’s Tower.
As for the rock, the fight isn’t over.
One camp, including the park’s own pages, sees magma that froze far underground and stayed hidden until erosion exposed it.
With Robinson’s careful survey on that side, Zavvada’s team sees lava that pondered in a crater at or near the ancient surface.
Same columns, same tilted beds, two very different stories.
My own bet is on the crater because it’s the only model that accounts for both the inward tilt near the tower and the flaring columns at its foot with one process.
A lacalith struggles with both, and a plain stock treats them as coincidence.
I’d give it slightly better than even odds.
And I’d drop it the day anyone got permission to drill.
That’s the real bind.
What survives above ground can’t decide it, and hardly anyone may carry a piece of it away.
So, the newest study took a different route and listened to the tower instead.
That seismometer belonged to Jeffrey Moore of the University of Utah, working with Katherine Volinger and Jan Bersk, a researcher at the Czech Academy of Sciences in Prague.
So this chapter runs back through the same Czech Academy that produced the crater idea.
Their paper Tower in Motion appeared in GSA Today, the Geological Society of America’s magazine in the March and April 2026 issue.
On October 12 and 13, they ran three identical broadband seismometers.
Climbers working under a park permit carried one to the summit where it recorded for 21 hours.
Another sat on bedrock at the foot of the south wall and a third on a flat boulder about 200 meters to the south.
For 19 hours, all three were logging together, 100 samples every second.
What they caught was the planet’s background hum.
Ocean waves hitting far off coasts send a slow rumble through the continent, and it showed up at every station.
Wind shoved at the rock, and the tower responded.
It sways in two main directions, roughly east to west at about 1.1 cycles/s and roughly north to south at about 1.2, with the stronger one switching back and forth at random, plus a twist around its vertical axis near two cycles per second.
The two sways nearly match because the tower is almost symmetrical around its center.
It’s the same family of motions engineers record in skyscrapers.
The motion is minute.
In a windy spell, the summit moved about half a micrometer, half a millionth of a meter.
And when the air was calm, usually around a tenth of that, stare all you like and you’ll never see it.
It still never stops.
And this is the detail I think matters most.
The team built a computer model and adjusted it until it swayed at the measured frequencies.
To match the whole tower had to be about seven times less stiff than lab tests on cores of the same rock.
8 gigap pascals against an average of 55.
The stone itself is strong, but the tower acts soft because it’s a bundle of columns whose joints have opened up.
So that seismometer was listening to a stack of separate pillars swaying together a little loose.
And it learned that without taking a single sample that has a practical side.
The authors say, “Knowing how a tower like this vibrates helps judge shaking damage and forecast which rock falls in an earthquake.”
A smaller study on a sandstone tower about 30 meters tall in Utah’s Cane Springs Canyon found the same two sways and a twist.
Devil’s Tower is that pattern on a giant scale.
A century of arguments centered on how this tower began.
And this study is the first to measure how it’s holding together now.
It’s a freestanding cluster of mostly five-sided columns about 49 million years old, swaying on the prairie like a tall building.
The boulderfield at its foot shows columns have come down over the ages.
Yet, the park service says no one has witnessed a significant column fall in recorded history, and it has company.
The Missouri butes came from the same burst of magma, and a forested hill in the Czech Republic may hold the best clue to how both of them formed.
Here’s what’s firm.
Devil’s Tower is phonolyte pfery, ignous rock that cooled slowly, split into giant columns once it was already solid, and was uncovered as erosion wore the land down during the past several million years.
So, the petrified stump is out, and so is the simple solid volcanic plug many of us learned about in school.
What can’t be proven yet is whether it cooled far below ground or pulled in a crater close to the ancient ground surface.
Whatever could have decided, it was carried off by the Bell Forch River ages ago.
Remember that line from 1,956 about the direction the ground slopes?
It was the first clue pointing at a crater.
70 years on, those beds still tilt the same way.
And up on the summit where a seismometer sat for 21 hours, the grass bends in the wind and the rock beneath it is moving too half a millionth of a meter at a time over and over.
While people below argue about its name, Bear Lodge has been swaying the whole time.
Somebody finally listened.
This has been Ambrose Wild.
Stick around for more videos like this one, where we take a place everybody thinks they know and find out what it’s really
