By: Elizabeth Yuko
These subterranean destinations from the 19th and early-20th centuries showcase some of America’s hidden history.
Cincinnati’s lagering tunnels are one of several underground landmarks across the United States.
Most cities have a handful of tourist draws, like museums, historic sites and outdoor activities, that bring visitors to the area. But in some cases, an area’s most interesting attraction might lie below the surface—literally.
Underground landmarks can be found throughout the United States and tell some of the stories otherwise hidden in history. These eight subterranean tunnels, chambers and bunkers offer a glimpse into the unseen parts of life.
In the center of Turkey lies an incredible rock formation with a mysterious underground city buried beneath.
During the late-19th and early-20th centuries, Cincinnati was among the beer-brewing capitals of the United States, says Aaron Deininger, executive director of Cincinnati’s Brewing Heritage Trail. Many of the breweries relied on underground cellars and tunnels they had built between the 1840s and 1880s to produce lagers, which require cold temperatures to properly ferment.
“This was a time before the invention and commercial use of mechanical refrigeration, so simulating a cave environment, combined with ice harvested during the winter months, allowed them to produce this style of beer,” he explains.
The city’s breweries continued to use its lagering tunnels even after refrigeration technology became available up until Prohibition, because the underground spaces were naturally cool and cost efficient. When the breweries closed down and the buildings were demolished, many tunnels were sealed or partially filled. “Sometimes new businesses utilizing the above-ground structures during the 20th century would use the cellars as trash pits and fill them with debris,” Deininger says. “Since most were constructed extremely well, they have been able to sustain long-term neglect, until being rediscovered a century later.”
Today, Cincinnati has the country’s largest concentration of pre-Prohibition brewing structures. More than a dozen of these underground lagering tunnels have been discovered to date, but Deininger says there might be more. Some of the old lagering tunnels are accessible via guided tour.
During the 19th and early-20th centuries, Cincinnati breweries fermented lager in cold underground tunnels.
Located in Milton, Wisconsin, the Milton House is a former stagecoach inn and stop on the Underground Railroad. The town’s founder, Joseph Goodrich, built the hexagonal-shaped inn as well as an adjoining commercial and residential space in 1844 near a pioneer cabin that dates to 1837. The structures are connected by an underground passage approximately 45 feet long and about 3.5 to 4 feet tall.
According to research and oral histories, freedom seekers on the Underground Railroad were brought to the cabin’s root cellar where they could enter the earthen tunnel. “They would use the underground passage to get to the root cellar of the stagecoach inn, where they could find relative safety and shelter…until it was time to move them to the next stop on their journey,” says Keighton Klos, executive director of the Milton House Museum. “At that point, the process would be reversed, and they would use the underground passage to move from the stagecoach inn into the pioneer cabin and into a waiting wagon that would move them to their next location.”
The Milton House Museum has operated as a historic house museum since 1954. Guided tours are offered year-round.
The Milton House was a stop along the Underground Railroad. Freedom seekers would travel by tunnel from a nearby cabin to stay in the former inn’s cellar.
Born a slave, Harriett Tubman became a famous "conductor" on the Underground Railroad, leading hundreds of slaves to freedom.
Michigan’s former Traverse City State Hospital—originally known as the Northern Michigan Asylum—opened its doors to patients with mental illness in 1885. The building was constructed with a state-of-the-art ventilation system, which involved large fans forcing air through underground tunnels then up flues in different parts of the structure. The tunnels were also used to move electricity, heat and hot water between buildings. In some cases, staff would walk through the tunnels to get from one building to another on the hospital’s campus.
Today, most of the tunnels below what is now The Village at Grand Traverse Commons have been blocked off or have caved in and contain hazardous materials. However, a 400-foot steam tunnel has been cleaned out and is now open to the public for guided tours.
The former Traverse City State Hospital in Michigan was constructed in the 1880s to include a state-of-the-art underground ventilation system to aid mental health patients there. Today, you can see one of the tunnels on a guided tour.
Hidden beneath the Indianapolis City Market lies a series of passageways connected via brick barrel-vaulted arches. It looks like a crypt but contains no bones. Known as the Indianapolis Catacombs, these are the remnants of the Tomlinson Hall building that was dedicated in 1886, says Kelly Harris, programs manager for the historic preservation organization Indiana Landmarks.
“Despite being designed as storage for market vendors [at City Market next door], the underground Catacombs space has seen many different purposes and events over time,” Harris says. “The space became a staging area for the events happening in Tomlinson Hall,” including bicycle stunt shows.
In 1958, Tomlinson Hall caught fire, destroying its entire upper floor. At the time, newspapers blamed a pigeon for starting the fire, accusing it of dropping a lit cigarette on the roof. “Today, all that remains is one arch—still standing next to the Indianapolis City Market—and the space we now call the Catacombs,” Harris says.
Indiana Landmarks began giving guided tours of the Catacombs in 2012, as part of tourism initiatives when Indianapolis hosted the Super Bowl. Because of construction surrounding City Market, Catacombs tours are unavailable in 2026 and 2027.
The Indianapolis Catacombs are full of brick archways. Market vendors once used the space for storage.
The Great Seattle Fire of 1889 destroyed 25 blocks in the city’s downtown. Rather than relocating to another part of town, most of the affected businesses rebuilt in the same location—after the streets were raised by more than 20 feet in places to help fix drainage issues in the hilly city. This left the first stories of storefronts below the surface, forming a network of connected cellars and basements known as the Seattle Underground.
The subterranean tunnels turned into a commercial district, where shoppers could run errands while avoiding the rain. The arrangement only lasted a few years, however; after a 1907 bubonic plague outbreak in Seattle, the tunnels were sealed and largely abandoned.
In the 1960s, when the city’s downtown was targeted for urban renewal, residents like journalist and local historian William “Bill” Speidel fought back. Speidel heard rumors about the underground passageways, and with the help of other Seattleites, he located the long-lost tunnels. He began offering underground tours shortly thereafter. Roughly 15,000 people took his tours of the underground city in 1965 alone. Renewed interest in the area staved off redevelopment, and the guided tours have been running ever since.
After the Great Seattle Fire of 1889 led to the creation of the Seattle Underground, shoppers visited the subterranean commercial district until it was closed less than a decade later.
Portland, Oregon, has its own maze of underground passageways, called the Portland Underground and better known as the Shanghai Tunnels. Located below the Old Town, Chinatown and downtown Portland neighborhoods, these tunnels connected the basements of taverns, saloons and seedier establishments to the city’s Willamette River waterfront.
Myths claim the tunnels were used to drug and kidnap unwilling sailors, but the network was actually constructed following Portland’s Great Flood of 1894 to help with drainage and transporting goods from the waterfront to neighborhood businesses. The interconnected passages were largely sealed off in the 1950s then rediscovered two decades later. Today, you can visit the tunnels on a guided tour.
Portland’s Shanghai Tunnels were built after the Great Flood of 1894 to improve the city’s drainage. They later fueled myths of men being kidnapped and forced to work as seamen.
Located in White Sulfur Springs, West Virginia, the Greenbrier resort was founded in 1778 and hosted five presidents before the Civil War (and several since then). The large hotel became a military command center during the Civil War, a diplomatic refuge during World War II and twice served as a military hospital.
Arguably, the Greenbrier’s biggest wartime role came during the Cold War. In 1958, U.S. Congress ordered the hotel to build a new wing to hide the construction of an emergency fallout shelter designed to house its members indefinitely in the event of a nuclear attack. Codenamed Project Greek Island and completed in 1962, this massive emergency relocation center is located 720 feet below ground and was diligently maintained in a state of perpetual readiness for the next 30 years.
The public didn’t know about the bunker until it was revealed in a 1992 article in The Washington Post. Three years later, the government terminated its lease with the Greenbrier, which then began offering guided tours of the once top-secret underground bunker.
The preserved communication room at the former Greenbrier Bunker in West Virginia. The federal government built the sprawling underground facility, which included living quarters and three congressional chambers, to protect the legislature in the event of nuclear war.
Located in Houston, the Buffalo Bayou Park Cistern was constructed in 1926 as a drinking water reservoir for the Texas city. Named for its resemblance to the ancient Byzantine cisterns beneath Istanbul, the underground reservoir spans 87,500 square feet—the size of 1.5 football fields—and has 221 concrete columns, each 25-feet tall. When it was functioning at full capacity, the cistern held 15 million gallons of drinking water.
After a leak was discovered that couldn’t be fixed, the cistern was decommissioned in 2007. Efforts to restore and repurpose the space began three years later, and it opened to the public in May 2016. Today, the Cistern is open for guided tours, performances and art installations.
Beneath Houston, you can see art installations and performances at the Buffalo Bayou Park Cistern, which operated as the city’s drinking water reservoir for more than 80 years.
The intent was to create a calm, shady spot for tired drivers.
Yellowstone's stunning natural beauty inspired the 19th-century push to set aside the land, where Indigenous people had been present for millennia.
The first drive-in opened in New Jersey in 1933.
Elizabeth Yuko, Ph.D., is a bioethicist and journalist, as well as an adjunct professor of ethics at Fordham University. She has written for numerous publications, including Rolling Stone, The New York Times, The Washington Post and The Atlantic.
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