For most people, the Denver International Airport (DIA) is a stopover on the way to a final destination or a Mile High City vacation. But for a select few, the airport is ground zero for a heap of shadowy, dark conspiracy theories fueled by the internet.

These rumors believe that everything from aliens to the Illuminati call DIA home, and they are so prevalent that the city’s paper of record compiled a guide to the most popular theories. Since 2016 the airport has publicly embraced the wacky ideas, featuring a museum-style exhibition of the least controversial theories and even hosting events around similar themes. But now DIA has gone a step further.

In the midst of a $650 million renovation of the airport’s Great Hall, DIA installed temporary walls in Jeppesen Terminal to keep people out of construction zones. And instead of a polite, “We apologize for our dust” sign, DIA and marketing agency Karsh Hagan went all in with the conspiracy theories.

One sign reads, “Since the airport’s opening in 1995, there have been endless rumors and theories. People say our underground tunnels lead to secret meeting facilities for the world’s elite. Our blue horse is thought to be cursed. Some believe we are connected to the New World Order, the Freemasons, and are home to lizard people.”

Another sign jokes, “What’s happening behind this wall? A. Gargoyle breeding grounds. B. A top secret freemason meeting. C. An improved airport experience.” The large graphics include pictures of brightly colored aliens, lizard creatures—and for all the cat lovers out there—a kitten with a foil hat.

There’s no debunking of theories on the signs, instead, they just direct viewers to “Learn the truth at DENFiles.com,” a website that explains the construction project and what travelers can expect. If you, too, want a look at the funniest construction signs around, they will stay up through the first phase of construction, which concludes in summer 2019.