On a cold morning back in January, I walked along the railroad viaduct that buffers 16th Street in Pilsen. Today the embankment is best known for its two miles of colorful murals, primarily between Halsted and Western.

You wouldn't know it from those artworks, but the spot where the bridge crosses Halsted Street was also the site of one of the bloodiest labor uprisings in Chicago history.

I first read about the Battle of the Viaduct in Union Made, Heath W. Carter's history of the social justice movement in Chicago’s churches. It described three days of violence in the city’s working-class immigrant neighborhoods during the Great Railroad Strike of 1877, or the Great Upheaval, which took place in various industrial cities across the country.

In Chicago, 30 people were killed by police and militia. Two hundred men, women, and children were injured. Of every American city that participated in the strike, Chicago claimed the most casualties.

The Battle of the Viaduct — or as it's sometimes called, the Battle of Halsted — describes one particular clash on July 26, 1877, the final and deadliest of three days of fighting. Armed forces shot at thousands of striking workers and supporters who'd gathered on Halsted Street near the bridge, killing several of them.

When I read about the skirmish, I’d already spent six years living in Pilsen, four of them on Halsted and 18th Street, where part of the melee was fought. But I'd never heard of the Battle of the Viaduct. How could I have been sleeping, quite literally, on the site of one of the bloodiest days in Chicago history?

That's how I ended up walking 16th Street, searching those murals for a sign of the battle. Starting in the early ’80s, Latino activists began using the wall as a canvas for protest art. Now, you’ll find everything from literary references to heartfelt memorials. At 16th and Newberry Avenue is a somber portrait of Marlen Ochoa-Lopez, the pregnant teenager murdered last year after being lured into a Southwest Side home. West of Carpenter Street, ghostly figures painted by Viktor Valášek honor the 100th anniversary of the Eastland Disaster, the catastrophic shipwreck that killed 844 Chicagoans.

But there are no memorials for the Chicagoans who died at the viaduct in 1877. The closest thing is on a stretch of wall on Morgan Street at 15th: a foursome of railroad workers swinging hammers in the sun, part of a tableau depicting 19th-century life in what's now University Village.

But the Battle of the Viaduct hasn't been totally lost to history. On May Day in 2010, Paul Durica — then a mustachioed grad student, now the Newberry Library’s Director of Exhibitions — staged a ragtag reenactment of the uprising. It was put on by Pocket Guide to Hell, Durica's walking tour company that paired Chicago history with guerilla street theater. Playing the role of socialist firebrand Albert Parsons, Durica led about 200 participants, some in period garb, to several key locations.

The ensuing faux fight, complete with old-timey cops armed with squirt guns and rioters tossing foam rocks, earned write-ups in the Chicago Reader, Vice, New York Times, and even Breitbart. He'd hoped it would raise the profile of the overlooked episode, rallying enough support for a permanent sign or plaque.

But a decade later, there's nothing beneath the viaduct at Halsted and 16th except for Metra signage and some overgrown ivy. “To me, it’s so strange that there’s nothing in the built environment acknowledging what transpired here,” says Durica, staring at the white wall.

After all, the events of 1877 marked the United States' first-ever general strike. To many, they represented the culmination of the labor unrest that had plagued the Gilded Age. In rapidly industrializing cities, laborers worked long hours for low pay, often from bosses who repeatedly cut wages following the Panic of 1873, the worst financial depression American had seen. Some observers dreaded an American version of the Paris Commune or a second Civil War, pitting foreign-born socialists and communists against capitalists. Unions, for the most part, didn’t exist yet.

“We’re talking about a time before the eight-hour workday and a century before the existence of OSHA,” says Peter Alter, chief historian at the Chicago History Museum. “Think about unsafe conditions, six- and seven-day workweeks, and a lot of difficulty for working people.”

That summer, railway workers responding to repeatedly cut wages clashed with armed forces, including 45,000 militiamen called by 15 states, the national guard, hired railroad militias, and federal troops commanded by President Rutherford B. Hayes, who was determined to restore rail service and break the strikes. When the strikes ended more than a month later, an estimated 100 people had been killed, with 1,000 arrested and millions of dollars of property destroyed.

“When you read the local newspapers from those days, they’re like, ‘Holy crap, what did we just go through? That was nearly a revolutionary moment,’” Alter says. “It’s kind of the same way some people saw the Democratic National Convention in Chicago in 1968.”

The strike sparked on July 16, 1877, when 40 railroad workers shut down rail traffic in Martinsburg, West Virginia, following their third pay cut that year. Laborers across the country followed suit, stopping work and rioting along major train lines. Fearing anarchy, officials sent troops to quell the strikes. Gun battles broke out, killing one worker in West Virginia and ten in Baltimore. Days later, in Pittsburgh, the state militia fired on strikers and their families, killing 20. In retaliation, protesters burned the Union Depot along with hundreds of engines and cars.

Next stop: Chicago. On July 24, 1877, freight hands and switchmen on the Michigan Central Railroad walked off the job after their employer refused to reverse its most recent wage cut. The headline of a writeup in the next morning's Chicago Tribune simply stated: “It Is Here.”

On the eve of Chicago's railroad strike — July 23, 1877 — 30,000 German, Polish, Irish, and Bohemian immigrants packed the intersection of Madison and Market Streets. They were there to hear Albert Parsons, the socialist leader Durica portrayed in his Battle of the Viaduct reenactment.

Originally from Alabama, Parsons enlisted in the Confederate army at 15, but came out the other side of the Civil War a radical antislavery Republican. He founded the Spectator, a newspaper pushing for civil rights for freed slaves in Waco, Texas, before moving to Chicago with his wife, Lucy Parsons (née Gonzales or Carter; Lucy left behind competing accounts of her heritage).

The Parsonses immersed themselves in Marxist organizing in Chicago, where Albert's oratory skills quickly earned him a substantial following. In the spring of 1877, he ran for Cook County clerk, representing the new socialist Workingmen’s Party, just narrowly losing. Allan Pinkerton, the 19th-century spymaster who ran the union-busting Pinkerton Detective Agency, wrote of Parsons in his 1878 book: “[He] is capable of making a speech that tingles the blood of that class of characterless rascals that are always standing ready to grasp society by the throat.”

That's more or less what Parsons did on Madison Street on July 23. “We are assembled as a Grand Army of Starvation,” the labor leader bellowed before the collected workers, riffing on the Union Army’s formal name, the Grand Army of the Republic. “It rests with you whether we shall allow the capitalists to continue to exploit us. Will you organize?”

The next day, Parsons was fired from his job at the Chicago Times and approached by two plainclothes police officers, who asked to escort him to City Hall under the guise of a meeting with Mayor Monroe Heath. Instead, according to Parsons’s 1887 autobiography, he was interrogated by police chief Michael Hickey and a group of 30 angry businessmen from the Board of Trade, some of whom called for his lynching.

The threats worked: Parsons and other Workingmen's Party leaders were spooked enough to lie low during the following days' strikes. But that didn’t stop a leaderless throng of workers from parading through Chicago’s streets, destroying property in their wake.

The press had harsh, sometimes xenophobic words for the strikers. One account described them as “hordes of ragamuffins, vagrants, saloon bummers, and generally speaking the dregs of society.” The Tribune wrote: “The rear end of this crowd was composed of a lot of as dirty, God forsaken looking little imps as ever blacked boots or sold newspapers, whenever they passed a fruit stand, each boy made a grab, and when they had passed, the stand was empty of apples, oranges, peanuts, etc., and the bewildered Italian seller hardly knew what had become of his wares.”

The strikers resented the stereotyping. “Look at me, look at my hands — do I look like a loafer or a laboring man?” an Irish boathand exclaimed during a speech to a small crowd. “We know who we’re fighting for and what we’re doing. We’re fighting those goddamned capitalists. Ain’t we?”

Authorities were doubly alarmed. Mayor Heath shuttered the city’s saloons and deputized several hundred citizens. Several aldermen formed their own militias of middle-class clerks and managers. A small band of Civil War veterans gathered in the 4th Ward; one alderman even deployed troops on horseback.

Mayor Heath initially ordered officers to fire blanks over the heads of workers, hoping to avoid a repeat of the Pittsburgh massacre. But as the chaos grew, police loaded their guns and aimed directly at strikers. One of the first recorded deaths occured on July 25, after 50 policemen tried to defend the McCormick Reaper factory at Blue Island and Western against 900 workers who rallied there to shut it down. The commander ordered the strikers to disperse; instead, the demonstrators showered the cops with stones. Shots rang out from police weapons, wounding two men.

A dozen pockets of isolated fighting erupted throughout the day. Five men were killed by police in a scuffle outside the Chicago, Burlington, & Quincy Railroad on 16th Street. One group of strikers raided Pribyl’s gun store on South Halsted. Police shot at a few Burlington rail workers and a gang of Irish youths at 16th and Halsted, killing three and wounding others, setting the stage for the next day’s horrors at the same location.

The word “battle” typically describes a fight between two organized armed forces. As such, the Battle of the Viaduct may be too glamorous a name for what transpired on July 26 in Pilsen.

“I’d say it was halfway between a strike and an urban riot,” says Richard Schneirov, a labor historian at Indiana State University and the author of Chicago in the Age of Capital.

On the morning of July 26, 5,000 protesters flooded Halsted between 12th Street (now Roosevelt) to the 16th Street viaduct. Some threw rocks at streetcars carrying commuters. In response, a squad of police fired at what were primarily Bohemian residents from Pilsen.

The strikers and sympathizers rarely committed to a full assault against the police, instead employing guerrilla tactics. They'd toss stones and lumber at their targets, then slip away into alleys when the police gave chase. It wasn’t just men fighting: One Irish woman, Mollie Cook, was arrested for firing at police from the window of her home on Halsted, and others joined the fray en masse.

“The police would look for these Bohemian women wearing only one stocking because they were taking them off to sling stones at police,” Schneirov says. “It was actually quite an effective weapon.”

Reporters milked the scene. “Outbreak of Bohemian Amazons!” read the Chicago Inter-Ocean; the Chicago Times described women with “brawny, sunburnt arms brandishing clubs.”

The crowd swelled throughout the day. The Bohemians were eventually joined by 500 stockyard workers from Bridgeport — some of them wielding butchers' knives and wearing their aprons — who'd marched to Halsted along Archer Avenue. Two boys in the front carried a banner reading “Workingman’s Rights.” After refusing to retreat from the Halsted Street bridge, they clashed with police for nearly an hour.

The violence peaked that afternoon, when police fired their muskets on thousands jammed atop the viaduct. Parsons later wrote in his autobiography that they even shot “sight-seers … killing several persons none of whom were even on a strike.”

While the Battle of the Viaduct raged, other skirmishes broke out nearby. At Turner Hall at 12th Street and Western, several hundred German craftsmen were meeting with their employers to bargain over an eight-hour work day. Amid the negotiations, a band of officers rushed in, killing a 28-year-old cabinetmaker and injuring others.

By mid-afternoon, the U.S. Army marched down Madison Street and took up position on the viaduct with artillery guns to support the police and militias. Two regiments arrived from the Dakotas, where they’d been fighting the Sioux. Facing 3,000 armed soldiers and militiamen — a force greater than that deployed in the Great Sioux War the previous year — most Pilsen and Bridgeport residents retreated into the night.

At 9:10 p.m., an Illinois National Guard regiment atop the viaduct commanded by Lieutenant-Colonel James Quirk rained musket fire on "straggling rioters," according to brigadier general Joseph T. Torrence's report, doing so once more at 10:30 p.m. “All was quiet the rest of the night,” Quirk reported.

In the end, the demonstrators' stones and clubs were no match for the authorities' guns. The Chicago Police and militiamen suffered no fatalities and 18 injuries during the three-day uprising. Meanwhile, the demonstrators mourned 30 dead, nearly half of whom were boys under the age of 18, and 200 injured.

Schneirov believes that the body count may have been higher, as some corpses were thrown in nearby limestone pits in lieu of a proper burial. “Could it be 50 or 60 dead? Yes, but I only documented 30.”

The Great Upheaval ended a few days later, but its impact would be felt for decades.

“It really starts much of the foundation for the growing clash between capital and labor,” says Larry Spivack, president of the Illinois Labor History Society. “In 1877, you had actual class warfare for the first time, with the state crushing these strikes while the press concocted stories about wild-eyed radicals trying to ruin America.”

Afterward, both sides prepared for the inevitable next round. When railroad bosses fired striking employees, organized labor federations sprung up in earnest, including the Knights of Labor and the American Federation of Labor. “The events of 1877 gave a great impulse and activity to the labor movement all over the United States and in fact, the whole world,” Parsons wrote in his autobiography.

Likewise, the Workingmen’s Party grew in political clout. It renamed itself the Socialist Labor Party (SLP) and elected three socialist state representatives and one state senator in Illinois, as well as five Chicago aldermen elected in the late 1870s.

Chicago’s business owners formed their own union of sorts, the Commercial Club, in 1877. Through the organization, men like George Pullman, Cyrus McCormick, George Armour, and Frederic Delano advocated for the use of the Illinois National Guard and U.S. Army for the suppression of labor unrest.

The Commercial Club later bought 600 acres north of the city and constructed Fort Sheridan, an army base designed so that troops could quickly combat another mass strike. (They'd do so in 1894, during the Pullman workers’ strike.) Meanwhile, Chicago’s richest man, Marshall Field, donated thousands of dollars to the city for cannons, ammo, and even a Gatling gun.

The Tribune took the side of the businessmen, editorializing three days after the uprising: "A few lives taken at the first saves human life in the end. … A little powder, used to teach the dangerous classes a needful lesson, is well burned, provided there are bullets in front of it."

Parsons, who’d been blacklisted by Chicago publishers following his firing from the Chicago Times, became further enmeshed in left-wing politics. He claims in his autobiography that in 1879, the Socialist Labor Party considered nominating him for President of the United States — an honor he had to decline because he was still under the age of 35.

Nine years after the Battle of the Viaduct, Albert and Lucy Parsons led thousands of people down Michigan Avenue in the first-ever May Day Parade, demanding an eight-hour workday. Somewhere between 30,000 and 40,000 workers walked off their jobs in Chicago, joining more than 300,000 strikers nationwide.

But three days later, the tide turned. On May 4, 1886, during a demonstration in present-day West Loop, an unknown culprit lobbed dynamite at police, killing seven officers and four bystanders, and wounding dozens more. Parsons and seven others were rounded up and convicted in a trial now considered a notorious miscarriage of justice. On November 11, 1887, Albert Parsons and four others were hanged in the Cook County Jail for their unconfirmed role in the explosion.

The events of May 4, now known as the Haymarket Affair, are a staple of Chicago history. The location of the bombing at 175 North Desplaines is marked with a $300,000 state-funded memorial, and you can sip a Lucy Parsons–themed beer at nearby Haymarket Brewery.

Meanwhile, Haymarket's predecessor remains unknown to most Chicagoans.

Why has the Battle of the Viaduct been all but forgotten? For one, labor history hasn't always been the easy sell it is today. 

But in a time that some are calling the Second Gilded Age, interest in Chicago’s role in the labor movement is on the rise. In 2012, the striking Chicago Teachers Union gained national attention for its aggressive approach to union organizing, and last year, Chicago elected six democratic socialists to the City Council — the most since the 1870s.

“There's been a surge of interest in this hidden history in the last few years,” Spivack says. “[The Illinois Labor Society] gets more and more requests for people who are looking for labor tours.”

Alter, for his part, believes the Battle of the Viaduct may be overshadowed by other major events of the late 19th century, like the Great Chicago Fire six years earlier, the Haymarket Affair nine years later, and the Pullman Strike six years after that.

“In the 20 years I’ve been [at the Chicago History Museum], there haven't been any exhibits about 1877,” Alter says. “In people’s minds, it doesn’t rise to the stature of Haymarket and the more famous Pullman Strike, even though they shared a lot of elements: the stoning of outsiders, destruction of property, tying up railroads. [It was] kind of a revolutionary moment.”

Spivack says an 1877 monument is on the Illinois Labor History Society’s agenda, but admits “it’s going to be a very complicated thing to do.” After all, it took decades for the Haymarket monument to even begin to become reality, even though most Chicagoans who were old enough to remember the uprising had long since died.

“I was in grade school when Studs Terkel and others started the Haymarket Workers Memorial Committee [in 1968],” says Spivack. “The resistance to it was profound.”

Still, several other cities have erected their own markers for the Great Upheaval in recent years, including Reading, Pennsylvania, Martinsburg, West Virginia, and Pittsburgh. In 2013, Baltimore even installed a plaque at Camden Yards, home of the Orioles.

Will Chicago be next?