Denver International Airport is preparing to open portions of a mysterious underground tunnel system that has long been plagued by conspiracy theories.

Officials announced plans this week to convert sections of the airport’s underground baggage tunnels into pedestrian walkways connecting concourses A, B and C.

The tunnels, which have long fueled speculation involving secret bunkers, “lizard people” and underground military facilities, will become an alternative route for passengers traveling between terminals.

Currently, travelers primarily move between concourses using the airport’s underground train system.

Denver Mayor Mike Johnston acknowledged the airport’s unusual reputation while discussing the project.

“Maybe along the way, travelers will finally get a closer look at the underground tunnels and decide for themselves what’s fact and what’s fiction,” Johnston said in a statement released by the airport.

Airport officials said the new pedestrian walkways are part of Denver International Airport’s broader “Vision 100” expansion plan aimed at preparing for future passenger growth.

Construction is expected to begin in 2027.

The project is estimated to cost between $300 million and $700 million.

It will be funded through airport revenue rather than taxpayer dollars, Denver International Airport CEO Phil Washington told CBS News.

Denver International Airport has long attracted conspiracy theories centered on its underground tunnels, unusual artwork and the airport’s towering blue mustang sculpture with glowing red eyes, nicknamed “Blucifer.”

Speculation surrounding the airport intensified after its opening in 1995 was delayed by more than a year and went billions of dollars over budget, according to reports.

The airport has also invested heavily in other upgrades in recent years, including train improvements, gate expansions and renovations to the Jeppesen Terminal.

The announcement quickly sparked reactions online, with many users joking about the airport’s decades-old conspiracy theories.

“Be prepared to fight the lizard people along the way,” one Reddit user wrote.

Others referenced the airport’s famous blue horse sculpture.

“Praise Blucifer,” another commenter joked.

Several travelers also welcomed the idea of having an alternative to the airport’s train system.

“We’ve only been asking for this since before the airport opened,” one Reddit user wrote.

Fox News Digital reached out to Denver International Airport for further comment.