Wikipedia provides a list of tunnels in the United States numbering well over 100 across almost every state. They range from railroad tunnels to highway tunnels, along with a few that go beyond transportation and are far more interesting. Here are a few of our top picks.
Kansas City’s Subtropolis Business Complex
Limestone deposits dating back 270 million years have been carved into what’s claimed to be the world’s largest underground business complex. More than 1,600 people report daily to take up work in businesses ranging from record storage and e-commerce to food distribution and retail manufacturing.
It’s a 55 million-square-foot artificial cave 160 feet beneath the surface with almost seven miles of paved roads. The temperature is a cool 65 to 70 degrees year-round.
2. Hidden Catacombs of Indianapolis
City Market is extremely popular, with thousands of people visiting every day. Underneath are the catacombs with dirt floors and multiple columns. It formed the basement of Tomlinson Hall, constructed in the 1880s. It burned down in the 1950s, but the solidly built basement remained in place. In old times, it was used for storage but is now available for parties, events, and tours.
3. Seattle Underground Abandoned City
The 1889 Seattle fire wiped out the city with the new city rising from the old as essentially a second floor elevated by roughly 22 feet. In the early years, businesses continued to operate underground until 1907 when they were condemned by the city and abandoned. In the 1950s, this long-abandoned underground city was opened for tours.
4. Dallas Underground Tunnels – Shops and Restaurants
There’s a complete tunnel system under downtown Dallas. The original goal when they were built in the early 1970s was to connect downtown buildings, complete with shops and restaurants. This is a great way to beat the Dallas summer heat. Today, some shops and restaurants remain, but several tunnels have been closed.
5. Los Angeles Prohibition Tunnels
The 1920s and prohibition inspired a great deal of creative thinking about how to make, sell, and consume adult beverages. This is an interesting tour of an underground tunnel leading to a speakeasy following directions scratched out on a bar napkin. Seems appropriate.
6. Tunnels Under the Colorado State Capitol
While not a tunnel system under the city of Denver, this tunnel under the Colorado State Capitol building offers a glimpse into an extensive steam heating system, storage for the only remaining marble to repair the building, and a few empty vaults. Don’t miss the cat footprints in the concrete!
7. Houston’s Seven Miles of Tunnels
Starting more than 80 years ago as a way to connect two buildings, it now covers over seven miles under downtown. It’s very convenient when you consider Houston weather: hot and hotter!
8. New York City Subterranean World
This is one of our favorites, chronicling the full range of underground tunnels in Manhattan up to 800 feet deep. It includes water mains and utilities, along with the 840 miles of subway tracks and 472 stations.
At four feet deep are a series of pneumatic mail tubes. Built in 1897, they were used to transport letters between 23 post offices until the 1950s. Also, watch for the ship found at 15 feet that dates back to the 1600s.
Don’t Try This at Home without Professional Help
Several of the abandoned tunnels are dark, damp, and musty. They could certainly do with a drainage system. You can also bet that the more modern tunnel systems have extensive drainage as well as ventilation systems.
That applies to any home project, including making sure your basement is waterproof. Complete waterproofing systems begin with interior drainage, sump pumps, and dehumidifiers.
The best place to start your basement project is with a free inspection from your local basement waterproofing and foundation repair experts.