A century ago, Centralia, Pennsylvania was a busy small town filled with shops, residents and a brisk mining business. Coal from local mines fueled its homes and its economy, and its 1,200 residents worked, played and lived as tight-knit neighbors.

Today couldn’t be more different. Centralia’s streets are abandoned. Most of its buildings are gone, and smoke wafts down graffiti-strewn highways where a prosperous town once stood. The formerly busy burg has turned into a ghost town. The cause was something that’s still happening beneath Centralia’s empty streets: a mine fire that’s been burning for over 50 years, resulting in the devastation of a community and the eviction and impoverishment of many of its residents.

Coal seam fires are nothing new, but Centralia’s is the United States’ worst and one of history’s most devastating. Before the 1962 fire, Centralia had been a mining center for over a century. Home to a rich deposit of anthracite coal, the town was incorporated after mining began in the 1850s.

Mining defined life in Centralia, from its rough-and-tumble residents to its seedier side. During the 1860s, the town was home to members of the Molly Maguires, a secret society that originated in Ireland and made its way to American coal mines along with Irish immigrants. In the late 1860s, the Molly Maguires are suspected to have committed a rash of violence within Centralia. As Pennsylvania historian Deryl B. Johnson notes, the Molly Maguires were implicated in everything from the murder of the town’s founder, Alexander Rae, to the death of the area’s first priest. “Some believe that the Mollies were guilty, while others claim that the Mollies were framed by owners of the mines who feared that the members of the Mollies and [other organizations] would organize the mine workers into unions," writes Johnson. Eventually, after a brutal attempt to subdue the Mollies and the execution of some of the groups’ suspected leaders in 1877, the crime wave ended.

Molly Maguires at a coal mine, circa 1870. (Credit: Kean Collection/Getty Images)

Centralia’s dependence on mining didn’t, though. By 1890, it was home to over 2,700 people, most of them miners or their family members. And even though the stock market crash and Great Depression struck a strong blow to the coal industry in Centralia, it didn’t kill the town.

It took a tragedy to do that, but it’s not entirely clear how the tragedy began. It seems to have started with the Centralia landfill, an abandoned mine pit that had been converted into a garbage dump in 1962. Trash was a thorny issue in Centralia, which was full of unregulated dumps, and the city council wanted to solve a problem with unwanted odors and rats.

In May 1962, the city council proposed cleaning up the local landfill in time for Centralia’s Memorial Day festivities. “This might seem like irrelevant, small-town history except for one thing,” wrote David Dekok in Fire Underground, his history of the fire: “Centralia Council’s method for cleaning up a dump was to set it on fire.” Though competing theories exist about how the fire was sparked, it’s thought that the Centralia dump fire sparked a much larger mine fire beneath the town.

Soon, a fire was raging in a coal seam beneath Centralia. It spread to mine tunnels beneath town streets, and the local mines closed due to unsafe carbon monoxide levels. Multiple attempts were made to excavate and put out the fire, but all of them failed. The reason, ironically, is the aftermath of the mining that defined Centralia for all of those years. There are so many abandoned mine tunnels in the area that one, many or all could be fueling the fire—and it would be prohibitively expensive and likely impossible to figure out which ones stoke the fire and to close off every single one of them.

Smoke rising from a large crack in PA Highway 61 caused by the underground coal fire, 2010. (Credit: Don Emmert/AFP/Getty Images)

As the years went on, the ground beneath the city itself became hotter and hotter, reaching over 900 degrees Fahrenheit in some locations. Smoke poured from sinkholes and gas filled basements. Residents started to report health problems and homes began to tilt. “Even the dead cannot rest in peace,” wrote Greg Walter for People in 1981. “Graves in the town’s two cemeteries are believed to have dropped into the abyss of fire that rages below them.” Earlier that year, a 12-year-old boy fell into a sudden sinkhole created by the fire, barely escaping death.

By then, it was too late for Centralia. Rather than put out the fire, Congress decided to buy out its residents, paying them to move. Then, in 1992, Pennsylvania moved to kick the holdouts out for good. All of Centralia’s buildings were condemned; its ZIP code was eliminated. Seven residents remained via court order; they are forbidden from passing down their property or selling it.

Today, Centralia still burns as one of 38 known active mining fires in the Pennsylvania.According to the state’s Department of Environmental Protection, the fire could burn for another century if left uncontrolled. Modern-day Centralia is known as much for the blaze—and the graffiti that covers its abandoned highway—as for the mining that once sustained it. And forget extinguishing the fire that has turned the town from a small mining center to a place infamous for its hidden blaze: As geologist Steve Jones told Smithsonian’s Kevin Krajick, “Putting it out is the impossible dream.”