On a windswept prairie near Trinidad, nestled in a grove of trees, a little-seen roadside memorial still preserves a place remembered as the "death pit."
It's where two women and 11 children suffered fiery deaths during a Colorado National Guard raid on a camp of striking coal miners - fueling a nationwide push for labor reforms even as it led to open war in the coalfields of southern Colorado.
It's called the Ludlow Massacre, and 100 years later, it's recognized as a watershed event for workers' rights in the U.S.
For descendants of the clash still living in the high desert plains around Trinidad, Walsenburg and Pueblo, the legacy is more intimate.
"It was a transformative event for southern Colorado, and many southern Coloradans still tie their identity to this," said state historian Bill Convery, who will be among the speakers recalling the events and their aftermath at "Remembering Ludlow Today," a panel discussion planned for 7 p.m. Monday at the History Colorado Center in Denver.
The talk is part of a yearlong push to highlight the centennial with poetry readings, lectures, museum exhibits and other remembrances, including events hosted by the United Mine Workers of America in mid-May. A new exhibit called "Memories of a Massacre: Perspectives on Ludlow" opens Saturday at the Pioneers Museum in Colorado Springs, telling the story through period photographs, original art and other media.
Many of the memorial events were arranged in cooperation with the Ludlow Centennial Commemoration Commission created by Gov. John Hickenlooper.
The group involves scholars, historians, Colorado National Guardsmen and labor union representatives, among others.
For historians, the 100th anniversary of the Ludlow attacks is an opportunity to reflect on how yesterday's struggles inform the present.
"It really is still a hidden history," said Dean Saitta, a professor of anthropology at the University of Denver, who framed the coalfield wars as a fight for equitable treatment. "Most Americans don't really appreciate what working people in the past did for us today."
More than 20 slain that day
The April 20, 1914, confrontation came during a tense miners strike at a Rockefeller-owned Colorado Fuel & Iron mine in Las Animas County, 125 miles south of Colorado Springs.
Miners and their families were evicted from their company homes seven months earlier by CF?&?I, which rejected the miners' calls for hourly pay, collective bargaining rights and safer working conditions at a time when mining-related deaths and injuries were common.
On the day of the massacre, a gunbattle broke out between miners living in a tent encampment and elements that included company guards and Colorado National Guardsmen, who had been mobilized in a bid to tamp down simmering tensions.
After miners fled into the hills, the militia led a raid that resulted in the camp's burning - and the deaths of 13 women and children who became trapped in their hiding place in a tent cellar.
They were among more than 20 people slain on the day of the Ludlow clash, most of them miners or their family members.
Two miners were slain in execution-style killings. Militia men later said they were shot while trying to escape.
Whether the fatal fire was set intentionally remains in dispute, as does the question of who started the gunbattle.
"Who fired first? I'm not sure we'll ever know," Convery said.
The Ludlow Massacre led to 10 days of skirmishes in which miners attacked a series of mines along a 40-mile stretch between Trinidad and Walsenburg.
In all, more than 70 people died in clashes along the Front Range between 1913 and 1914 in what has become known as the Colorado Coalfield War, according to "Blood Passion," a 2008 book by former Los Angles Times writer Scott Martelle.
After the massacre, the public threw its support behind the miners, and newspapers "crucified" John D. Rockefeller Jr., who launched the nation's first public relations campaign, hiring a former newspaper man to "spin" the conflict, said Karin Larkin, a professor of anthropology at the University of Colorado at Colorado Springs.
Rockefeller also launched a "company union" meant to investigate and address workers' grievances - a measure that stopped far short of the strikers' demands.
It wasn't until the labor reforms of the 1920s and 1930s that workers began seeing the types of improvements sought by the miners, Larkin said.
"Things that we sort of take for granted today - the 8-hour workday and child labor laws - are a direct result of these struggles," she said.
At the time, Ludlow miners were paid by the ton of coal they extracted and received no pay for what mine operators called "dead work," such as blasting tunnels, shoring up mine walls and ceilings and laying tracks used to transport the coal.
The workday began before sunrise and ended after sundown, and to help support their families, boys were put to work starting as young as age 8.
The camp employed a workforce of 1,200 miners, most of them immigrants from diverse backgrounds. They represented 121 nationalities, and more than 20 languages were spoken in the camp.
Mine operators controlled mine housing, the jail and the company store, which charged exorbitant rates.
At the height of the conflict, forces associated with CF?&?I routinely fired guns over the heads of those living in the tent city, and they kept floodlights on the camp throughout the night.
'This is living history'
The bloody chapter in Colorado history still stokes passions among descendants of those involved, said David Mason, a Colorado College English professor and author of "Ludlow," a verse novel based on the historical record.
Towns around the memorial site are populated with the descendants of National Guardsmen, sheriff's deputies, mining officials and miners - some of whom remain divided over questions of who drove the violence, Mason said.
"This is living history, and people feel very strongly about it on both sides of the story," he said.
In 2003, vandals damaged the memorial, hacking off the limbs of figures representing the victims. The vandals were never caught, leaving their motives an open question.
Funding poured in from across the world to cover repair work, and the memorial was rededicated in 2005.
The memorial - established by the United Mine Workers of America - invites visitors to descend stairs into the pit where the women and children were found.
But the Ludlow Massacre is seldom taught in Colorado schools.
"It affects most people's daily lives, in terms of labor relations and laws," Larkin said. "Yet most people don't know much about it."