6 Strange Conspiracy Theories Surrounding the Denver Airport

On February 28, 1995, the Denver International Airport (DIA) opened its doors and its runways to the public after falling over a year behind schedule and spending a reported $2 billion more than its original budget had dictated. 

The massive new airport didn’t just take up lots of time and money—it also took up a lot of space: More than two decades later, it’s still the largest airport in the United States by area (53 square miles) with the longest commercial use runway available in the country (runway 16R/34L is 16,000 feet long—approximately three miles). DIA replaced Denver’s old Stapleton International Airport, which was plagued by problems (runways too close together, a general lack of space for necessary expansion), and its creation helped meet some basic needs that Stapleton simply couldn’t. Denver needed more room to serve the various airlines that had made—and wanted to make—the Mile High City a hub of operations, and DIA did just that.

That all sounds normal enough, right? A city needed a new airport, and it got one, even though it took a lot more money and time than originally planned, as so often happens with large-scale public works (although there is some debate as to who actually funded the airport, but we’ll get to that). But people have wondered if DIA—giant, expensive, strange DIA—is home to something far more sinister ... like a conspiracy. Or a lot of conspiracies.

1. Denver International Airport's runways form a hate symbol.

Although one of the underlying themes of the various conspiracy theories regarding DIA holds that Stapleton was a fine airport and didn’t need to be replaced, there is one inarguable point: the runways at Stapleton were not smartly laid out. The parallel runways were too close together for safe landings in bad weather, which happened around 150 days a year and cut the number of arrivals an hour from 80 to 36. DIA doesn’t have the same problem, but it does have something far more nefarious: a shape that many people have noticed looks curiously like a swastika, at least from the air. Taken on its own, such a shape could be brushed off as being just a really terrible piece of planning, but combined with everything else, it all looks very odd indeed. 

2. Denver International Airport is involved with biological warfare.

Leo Tanguma’s two murals, which take up wide swathes of wallspace in DIA’s baggage claim, might have some nice names—they are called “Children of the World Dream of Peace” and “In Peace and Harmony with Nature”—but their actual content is terrifying. Death-masked soldiers with guns stalk children, animals are dead and kept under glass, and the entire world looks to have been destroyed. As if being at the airport isn’t bad enough.

Some believe the murals at Denver's airport feature doomsday scenes. It doesn't help that an inlay on the floor features the letters "Au" and "Ag." Though this nod to gold and silver is appropriate—Colorado does have a rich mining history, after all—some believe the letters represent a dangerous strain of hepatitis that could serve as a biological weapon. Those two symbols, coupled with the unnerving mural, have fueled a conspiracy theory that the airport could be a hub for biological warfare. 

To his credit, the narrative of Tanguma’s murals ends on a happy note—with all that peace and harmony stuff—and the artist himself has said, “I have children sleeping amid the debris of war and this warmonger is killing the dove of peace, but the kids are dreaming of something better in the future and their little dream goes behind the general and continues behind this group of people, and the kids are dreaming that [peace] will happen someday. See how the little dream becomes something really beautiful, that someday the nations of the world will abandon war and come together.” Still, the last place anyone wants to see depictions of death and destruction in an airport.

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3. Denver International Airport was built by a secret organization.

There is one very weird marker that’s hard to ignore: a dedication marker and capstone that’s been placed over a time capsule (which supposedly includes a credit card, Colorado flag, and DIA opening day newspapers, among many other things) that is set to be opened in 2094. The symbols on the marker are associated with the Freemasons, a charitable organization that is often subject to their own conspiracy theories. The marker also mentions the “New World Airport Commission,” an organization that doesn’t actually exist (or does it? Our brains are spinning!) but appears to be taking credit for building the entire airport. However, the contributors listed as part of the so-called NWAC, including an architecture firm and a metal company, do exist. And they just make buildings and metals. Well, probably.

4. Denver International Airport has mysterious tunnels.

The airport is home to a number of tunnels, including a tram that goes between concourses and a failed automated baggage system. That all sounds normal enough, but there is definitely something weird about that automated baggage system—mainly, that it cost a lot of money and then never actually worked. The system, which failed pretty spectacularly when it was first tested and just never got better, was one of the reasons for DIA's delayed opening. By 2005, most of the airport’s concourses had abandoned it totally, making both its bloated price and long delays feel like even more of a failure—or at least a really weird way to cover up the building of tunnels.

5. Denver International Airport is the headquarters for an underground government.

But where do the tunnels go? Perhaps to some kind of underground bunker? Most of the people who believe in the various conspiracy theories regarding DIA seem to think that the airport is actually the headquarters for something far nastier than just an airport—like the New World Order or our own American government. This idea might sound pretty wild—but there is something very strange to back it up: buried buildings.

As the story goes, when DIA was first being built, five massive buildings were built somehow incorrectly. Instead of being blown up or otherwise dismantled, they were buried. Although theorists say that a construction worker ultimately blew the whistle on this very weird practice, finding his original testimony on the subject is almost impossible. 

6. Denver International Airport's giant horse statue is cursed.

It’s hard to deny the weirdness of DIA’s unofficial mascot. The massive horse statue, called “Mustang”—and dubbed "Blucifer"—has already killed at least one man. At 32 feet tall and 9000 pounds (it’s made out of fiberglass), “Mustang” is huge and imposing, and its glowing red eyes don’t help matters. This thing is giant and really scary—and it killed the man who made it. Really. Artist Luis Jimenez died in 2006 when a piece of the sculpture’s head broke off and severed an artery in his leg. His children finished the horse. Some believe the horse is cursed, and that its glowing eyes represent the Four Horsemen of the Apocalypse (they're actually a nod to Jimenez's father, who had a shop that sold neon lights).

A version of this story originally ran in 2016; it has been updated for 2021.