In 1921, ten thousand West Virginia coal miners took up arms against their bosses, and nobody had seen it coming.

Imagine, for a minute, that somewhere deep in the mountains of southern West Virginia there’s a rogue army on the move. Most of them are immigrants hailing from all across Europe, some of them are black Southerners, and a contingent of these militants was displaced from nearby farms. As they march, the August sun spills through the towering trees overhead. They’re singing about how they want to hang the local sheriff, who’s deputized hundreds of men to meet them in pitched battle just across the county line.

This may seem implausible to you, but not too long ago upwards of 10,000 coal miners – even double that number, by some estimates – participated in an armed revolt in the United States, going against local, state, and federal authorities as well as their own union. Back in 1921, when a decade of class war in the area culminated in the Battle of Blair Mountain, people couldn’t fathom it either. And yet, against all odds, it did happen: the largest armed rebellion in the country since the Civil War.

“The time has come… for me to lay down my Bible and pick up my rifle and fight for my rights,” one participant told a reporter at the time, according to Lon Savage’s book Thunder in the Mountains: The West Virginia Mine War 1920-1921.

What makes these miners’ armed resistance so remarkable isn’t the size of their force or their willingness to use violence. It’s that despite a seemingly hopeless and desperate situation, when most of their official leadership had begged them to give up, they didn’t.

At the time, miners in West Virginia lived primarily in unincorporated towns that were completely controlled by mine owners. They lived in company housing and were generally paid in scrip to be used at company stores with heavily marked up prices. Their bosses controlled the political system as well, and operated with impunity. They forced workers to sign “yellow-dog contracts” disavowing union activity as a condition of employment, and employed ruthless mercenaries from the Baldwin-Felts Detective Agency, a notorious private paramilitary squad, to suppress any attempts at organizing.

“Southern West Virginia had generally become the possession of New York, Philadelphia, Boston, Baltimore, and London,” historian Corbin writes in Life Work, and Rebellion, referring to the distant cities where these companies’ wealthy owners resided. “By 1900, absentee landowners owned 90 percent of Mingo, Logan, and Wayne counties… By 1923, nonresidents of West Virginia owned more than half of the state and controlled four-fifths of its total value.”

Mingo and Logan counties – south of the state capitol and near the border of Kentucky – would become the epicenter of this war between labor and capital.

The Battle of Blair Mountain in August 1921 didn’t materialize out of nowhere. It happened against the backdrop of the United Mine Workers of America’s effort to organize the state, the only non-union mining territory in the nation at the time. It also followed a series of strikes, many of them spontaneous and independently organized. The Baldwin-Felts squad enforced the coal companies’ rule, evicting miners who spoke up and sometimes attacking them and their families. And for their part, the miners regularly fought back, carrying out frequent guerrilla-style assaults on non-union mines, scabs, and company thugs.

“That is the trouble with this country today – that it is ruled by gunmen,” J.H. Reed, a 27-year-old black miner originally from Alabama, told the US Senate Committee on Education and Labor as part of the committee’s hearings on West Virginia coal fields in the summer of 1921. “The thing here is that [being] a man is the same as being in slavery.”

While these miners had plenty of grievances about their jobs, including frequent complaints that employers would underpay for the amount of coal workers had mined, the presence of the Baldwin-Felts played a major role in the escalation of the conflict.

“Southern West Virginia was an industrial police state, more or less,” local historian Doug Estepp told PBS “The Mine Wars,” a 2016 episodeof its long-running series American Experience.

With the companies acting in unison and controlling all aspects of miners’ lives, the men had little recourse. What might’ve been more run-of-the-mill strikes escalated into gun battles, ambushes, and murders as miners pushed to the brink decided to shoot back. During a yearlong strike in nearby Kanawha County in 1912 and 1913, miners and company thugs fought what’s now called the Paint Creek Mine War. And despite a brief respite during World War I – when workers enjoyed greater benefits thanks to federal intervention on behalf of the war effort – a post-war clawback by mine operators touched off the struggles anew. In the town of Matewan, a now-famous shootout between Baldwin-Felts men and locals escalated the conflict in 1920, inspiring thousands of miners, convincing them that victory – however fleeting – against their oppressive conditions was possible.

In some respects, it might be easy to look back at long-past history and think of the Battle of Blair Mountain as inevitable. After all, it capped off a decade of escalating struggle, and soldiers returning from war refused to tolerate their subjugation, much like black vets would later spur the Civil Rights Movement.

And millions of workers participated in a wave of post-war strikes, according to Robert Shogan’s 2004 book The Battle of Blair Mountain: The Story of America’s Largest Labor Uprising. But despite that widespread struggle and histories of armed class warfare throughout the country, what happened in southern West Virginia was an anomaly.

Historian Beverly Gage summed it up well for PBS: “At a moment when Jim Crow is tightening, at a moment when the United States is passing immigration restrictions, at a moment when attempts to organize are increasingly being marginalized, and at a moment when radical ideas that had been really popular before the war are increasingly being pushed out of the American mainstream, this idea that a mass group of armed men, black and white, immigrant and native born, expressing ideas that often didn’t have a lot of voice left by 1921, this was a really radical moment.”

It may be precisely that repressive context that led to so many deciding to take up a seemingly hopeless cause of armed rebellion. Many believed they had no alternative.

The miners technically “lost” – when federal troops arrived, the striking workers packed it in and went home. But most didn’t surrender, instead slipping into the hills. Despite hundreds facing legal charges for the revolt, hardly anyone was found guilty. Future laws, particularly the National Labor Relations Act of 1935 that banned blacklisting and formalized a worker’s right to organize, addressed some of the cruel conditions their struggle highlighted.

Conditions today are different, and yet there are obvious parallels with Gage’s observation – a prison-industrial complex dubbed “the new Jim Crow” by author Michelle Alexander, heightened restrictions on immigrants and refugees, and a resurgent and emboldened white supremacy, not to mention a growing militant response on the left. American society is undoubtedly fractured and polarized, aided by deep and growing racial and economic disparities. To some, things feel dire, maybe hopeless. But if the Battle of Blair Mountain teaches us anything, it should be that things aren’t always what they seem on the surface, and that just when resistance feels futile, there may be a furious and unexpected revolt about to erupt.