Denver airport to build walkways between concourses

Driving the news: Denver Mayor Mike Johnston and DIA CEO Phil Washington announced the plans Tuesday as part of preparation for the airport to eventually reach 100 million passengers a year.

How it works: The walkways will weave through parts of the airport's underground passageways, part of the existing baggage system. Those tunnels hold secret pathways and bunkers used by secret societies, according to one of the many legends.

• Construction is expected to start in 2027 — about the same time the main terminal build-out nears completion.

What they're saying: "We've heard loud and clear that easier, more reliable ways to move between concourses has been a top priority," Johnston said in a statement.

• "And who knows," he added, "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."

The big picture: The airport is in the middle of a massive expansion, adding 39 gates in recent years and renovating the Great Hall in the Jeppesen Terminal.

• It invested $75 million into upgrading the train system between terminals and is promising more improvements in the years ahead.