Despite the signs, the airport’s official line is surprisingly mundane. It’s all part of the brand, spokesperson Emily Williams told the Denver Post. “It’s a fun way that we can engage with our passengers,” she said. Definitely not a cover-up, then.

The stories themselves date back more than two decades, popularized through a combination of internet whisperings, blurry video footage, and a 2012 episode of truTV’s Conspiracy Theory with Jesse Ventura. Depending on who you ask, the airport’s variously controlled by Freemasons, fascists, the Illuminati, aliens, lizard people, or some hellish combination of all of the above. Others will tell you that the tunnels below the airport lead to a kind of Noah’s Ark, capacity five million, for the forthcoming environmental apocalypse. (No word as yet on how to get on to that list.)

However bonkers the stories might appear, conspiracy theorists advise against making light of them—or the posters. “It’s right in your face,” naturopath Len Horowitz told the Post. “They’ve taken all of the quirkiness of those who are considered foolish conspiracy theorists, and conspiracy theories, and blended it into their mixture of propaganda for damage control.”

Just what you’d expect of giant reptiles with an eye on world domination.

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