The monolith located in Bellvue, Colorado, sits on top of a hill (Credit: Kenna Hughes-Castleberry/The Debrief).

Return of the Monoliths: I Visited One of the Recent Monolith Sites. It Wasn’t What I Expected

Mysterious monoliths are once again springing up in odd and remote locations around the world, particularly in North America. Among the latest appearances of these unusual mirrored structures, one recently appeared in the Nevada desert in mid-June, followed closely by another monolith appearing ten days later in Bellvue, Northern Colorado.

Given that Bellvue is about an hour away from where I live, I couldn’t resist the opportunity to see one of these mysterious objects for myself.

There doesn’t seem to be an overall pattern to their appearance, but whoever is behind the monoliths (possibly the work of copycats, or maybe even a collective belonging to a larger organization), they do know how to get everyone’s attention with their unique construction and placement, resulting in waves of media attention following each appearance.

Monoliths also have fairly deep roots in science fiction, particularly as methods of communication from other (usually alien) societies, which further amplifies their intrigue. Given their cultural significance, before diving into the history of these mysterious monoliths, let me quickly clarify that I approach this topic with skeptical curiosity. I’m curious to know why someone would go to all the trouble to erect one of these structures, which appear to be made with everyday items like poured concrete and possibly sheet metal (sorry to burst anyone’s bubble that hoped this could be signs of alien contact, and yes, I’m an X-Files fan, too).

I pondered questions like these as I began to make my way north toward Bellvue.

A Brief History of the Monolith Appearances

In 2020, multiple different types of monoliths appeared across the globe. The structure seemed to be the same for the first three monoliths: a long, tall tower made of mirrored glass with all four vertical sides the same size.

In the case of the first three appearances, the monolith disappeared and then seemed to “reappear” somewhere else (though whether it was the same structure or something that looked similar is unknown).

It should also be mentioned that in several cases, the monoliths have seemingly “disappeared,” although in several instances it is known that they were dismantled and removed by authorities or landowners (as was the case with the monolith in Bellvue shortly after I visited it).

On November 18, 2020, the first monolith appeared in Utah’s Red Rocks County, creating a media circus of fascination mixed with speculation. This monolith quickly disappeared (with a YouTuber claiming to have removed the structure). The second monolith appeared nine days later, on November 27, 2020, in the Romanian city of Piatra Neamt. This second monolith also disappeared on December 1, leaving a large hole in the ground.

The third monolith quickly followed the first two, popping up in Pine Mountain in Atascadero, California, on December 2, 2020. According to a Vox article, the third monolith was disassembled and reappeared elsewhere on December 4, though I haven’t seen other articles mention the reappearance of the California monolith.

It’s important to note that each of the three appearances differed slightly. According to one article, the Romanian Monolith was covered with circles, while the Utah monolith had a smooth surface. They all generally seemed to be the same shape and size, which is why they are often grouped. I should note here that this does not mean they’re connected, though the structures are more similar than the ones that follow these three appearances.

After December 2020, the world seemed to go a bit monolith-crazy as copycat structures popped up around the globe, from Pennsylvania to the Netherlands to Joshua Tree and beyond. One headline after another showcased new monolith “appearances,” even if later they seemed to be proven as mimics or faked entirely. A Business Insider article claimed that December 2020 had over 87 monolith sitings.

Suddenly, all monolith sightings stopped, creating more of an aura of mystique around them as they faded from headlines.

Then, in March 2024, a monolith was spotted on the Welsh landscape. In mid-June 2024, another mysterious monolith appeared in the desert outside Las Vegas. Comparing photo images with the original three monoliths, it seems more similar to those structures than others, as it is a tall, uniformly shaped tower. Las Vegas authorities later took down this monolith. Less than two weeks later, the Colorado Monolith appeared.

Now, with more structures reappearing, the media and the general public are beginning to lean into monolith mania again, connecting these structures with science fiction references, perhaps to understand better why these monoliths are reappearing.

The Science Fiction Roots of Monoliths

With each monolith appearance, the media usually references extraterrestrials in some fashion. This is mainly due to the popular culture connotations of monoliths, such as Stanley Kubrick’s 2001: A Space Odyssey.

As a science journalist and science communicator, I am fascinated by the connections between science fiction and science fact, especially when we can utilize science fiction techniques to make science more digestible and accessible to all audiences.

However, in the case of the monoliths, little factual science is being communicated. Instead, awe, curiosity, and speculation swirl in an almost impenetrable fog as people wonder if aliens could have made these structures.

It’s easy to see why people may ask this, as 2001: A Space Odyssey is probably the most popular reference to monoliths and uses a monolith in the film as a way for aliens to communicate with humans. In a later interview, Kubrick stated that, “From the very outset of work on the film, we all discussed means of photographically depicting an extraterrestrial creature in a manner that would be as mind-boggling as the being itself.”

However, 2001: A Space Odyssey isn’t the only science fiction work that references or uses monoliths as plot devices. My personal favorite is science fiction writer Robert Charles Wilson’s use of the monolith in his 2001 book Chronoliths, where strange monoliths appear across the globe, made of an indestructible unknown material. The monoliths in Wilson’s book also bear an inscription to a mysterious warlord named Kuin, who had a military victory 20 years into the future. When I heard about the Nevada monolith,  I actually texted a single word to my husband, who introduced me to Wilson’s writings: “chronoliths.”

In both of these literary cases, monoliths tie back to an unknown extraterrestrial species, making the connection all too tempting for anyone to wonder about as more real-life monoliths appear.

My Own Experiences with the Colorado Monolith

After an hour of driving north, I found myself not in an alien landscape, but instead outside a dairy farm. The nearby Howling Cow Café and its accompanying dairy business made the place in the middle of nowhere seem more charming.

Fortunately for monolith seekers like me, a sign on the establishment’s front door also read, “For the monolith, walk by the fountain and look past the trees.”

Following these directions and squinting in the bright Colorado sun, I soon saw the mirrored structure atop a nearby hill. Excited, I moved closer, only to realize I couldn’t touch the monolith as it was on private property. Like the other nearby spectators, I took many photos and videos, my mind trying to capture and make sense of what I was seeing.

I expected something more mysterious. After all, with the media hyping the monolith’s reappearance so much, it seemed like I should have had some sort of emotional reaction to it, or perhaps be stunned into silence. Instead, I felt something more akin to uncanniness, as the monolith appeared like a door in the wide Colorado sky, waiting for someone to step into it.

The Colorado monolith is most certainly a mimic structure, as it’s wider than both the Nevada and Welsh monoliths. While the dairy farm owners claimed not to know anything about its origins, it is possible, like the other monoliths, that someone in the nearby vicinity knows more but is keeping quiet. At least, that seemed to be the case for the Howling Cow Café (and has been in the past for other “convenient” monolith appearances next to businesses).

Even if this structure doesn’t fit with the others, it doesn’t mean it won’t make you feel on edge. As I turned from the monolith to head home, I caught myself looking back, as if feeling it track my movements.

While I’m skeptical about these monoliths’ otherworldly origins, there is one thing I’m not skeptical about: the power of a good mystery.

Update: The monolith near Bellvue, Colorado has been removed since the author’s visit to the location. Also, The Debrief’s French correspondent and frequent contributor Baptiste Friscourt has shared with us that the monoliths appear to be the work of “an international collective of artists.” The current whereabouts of the Bellvue monolith since its removal are unknown, as is the identity of its creator(s).

Kenna Hughes-Castleberry is the Science Communicator at JILA (a world-leading physics research institute) and a science writer at The Debrief. Follow and connect with her on X or contact her via email at