Discover 5 U.S. Cities With Secret Undergrounds

Indianapolis, Indiana

When you think of expansive catacombs stretching out beneath a city, you likely think of Paris. However, did you know that you can find historic catacombs in the United States as well? In fact, you can even tour these tunnels in Indiana today!

Unlike those in Paris, the Indianapolis Catacombs aren’t actually used to store and bury human remains. Instead, the Indianapolis Catacombs are actually just a series of underground tunnels and spaces often used for more convenient transportation.

The Indianapolis Catacombs comprise 20,000 square feet of different passageways. They are located beneath the northeast corner of Market and Delaware, near the Indianapolis City Market. Historically, these passageways were used to easily transport goods to and from the marketplace. Thanks to period tours organized by the Indiana Landmarks, this underground marvel may not be a secret to locals, but it can easily go unseen by visitors!

Kansas City, Missouri

A massive business complex carved into an artificial cave beneath the Earth’s surface may seem like something out of a science fiction novel. However, in Kansas City, you won’t need to turn to a book or television for this curiosity. 

The SubTropolis is a business complex as far underground as 160 feet. It was established inside the Bethany Falls limestone mine, specifically inside a 1,100-acre artificial cave. The complex has the trademark for the phrase “World’s Largest Underground Business Complex.”

Much of this cave is carved from limestone, a naturally occurring material. The limestone deposit itself is thought to be 270 million years old!

Seattle, Washington

Before learning about the cities with secret undergrounds in Washington, it’s important to learn a bit more about the history of Seattle—specifically, the Great Seattle Fire.

The Great Seattle Fire occurred on June 6, 1889. On this day, a little after two in the afternoon, a glue pot was overturned inside a carpentry store. This little accident sparked a huge fire that ravished the city of Seattle. In fact, even to this day, the Great Seattle Fire is considered to be the most destructive fire ever in the entire history of the city. After the fire was extinguished, rebuilding was required. Other problems also plagued the city prior to this period of rebuilding, such as flooding.

To solve many of these problems, two ideas emerged: all buildings should be made of masonry, and the city should be regraded at a higher level. As a result, when the city was raised, much of the remains of the former city fell into disuse, an underground many outside of the city may not be aware of.

Prior to the rebuilding of Seattle, the Seattle Underground was the ground level for the city. However, today, these passages and rooms act as the underground beneath the city since being regraded. Unlike other cities with secret undergrounds where much of the area can be toured, only small areas of the Seattle Underground have been restored. As a result, much of it is not safe for tours. In the safe areas, however, several different tours run.

Dallas, Texas

The Dallas Pedestrian Network (also known as the Dallas Pedway) may not be a huge secret to locals. In fact, when it comes to the Texan heat in the middle of summer, this underground city can be one of the best ways to beat the heat!

The Dallas Pedestrian Network is a series of underground walkways beneath Downtown Dallas. However, these aren’t ancient tunnels chocked full of history to explore. Instead, during business hours, you’ll find that these passageways offer different restaurants and businesses to explore.

 Vincent Ponte is behind this interesting underground city. Born in Montreal, he also helped create the underground city in his hometown!

Denver, Colorado

Unlike other cities in the U.S., the secret underground tunnels located beneath the capitol building in Denver are not open to the public. These tunnels were originally created for the purpose of carting coal around the building. Historically, coal was used as a main heat source in the Colorado State Capitol building. Today, they serve a similar but modernized purpose. Instead of coal, the underground tunnels are used for maintenance and essential infrastructure such as wiring.