In Mexico’s state of Chihuahua, some 115 miles from the U.S. border, there is a seemingly unremarkable grassy hill just north of the town of Galeana. Look closely, though, and you might see century-old bullet casings rusting in the grass, and a slight depression at the top where a historic act of revenge is carved into the ground.

In 1882, years after an Apache encampment was massacred by Mexican troops, this is where the tribe’s legendary leader Geronimo and his men came to avenge the killings, burning Mexican commander Juan Mata Ortiz alive in a pit at the top of the hill. “They told the Mexican commander, Juan Mata Ortiz, ‘no bala, no cuchillo, no lance, pero lumre,” says Nelda Whetten, a lifelong resident of Chihuahua. “As in, you're not going to have a quick death—no bullet, no arrow, no lance, but fire.”

Geronimo’s quest for revenge began decades earlier, sometime during 1858, when an unprovoked attack launched the 29-year-old Apache (then known as Goyaałé) into a lifetime of war. While he and others were gathering supplies in Janos—a town just down the road from what would become the Mormon colony of Colonia Dublán—a company of 400 Mexican soldiers attacked their unguarded encampment. Recounting the raid in his 1905 autobiography, Geronimo wrote, “When all were counted, I found that my aged mother, my young wife, and my three small children were among the slain.” More than 100 Apache women and children were killed, but only Geronimo’s family was destroyed so thoroughly.

Geronimo assumed a leadership role among the Apaches, seeking vengeance for the raid. “We will attack them in their homes. I will fight in the front of the battle,” he wrote. “If I am killed no one need mourn for me.” Geronimo’s revenge campaign would last longer than he or anyone else would have expected, as he and other Apaches spent the next several decades intermittently raiding Mexican towns and military encampments, seeking to exact vengeance on their enemy several times over.

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The ambush that occurred on the grassy hill at Chocolate Pass, just north of Galeana, was one of the most infamous of his acts of revenge. On November 13, 1882, a band of Apaches under the leadership of Geronimo and Chief Juh ambushed Mexican forces. Their target: Juan Mata Ortiz, the commander of the town’s Mexican garrison. He was particularly hated for his role in the Battle of Tres Castillos two years earlier, in which more than half of the Apaches were killed and the majority of the survivors taken prisoner.

“The Apaches went into the town of Galeana, because they knew Ortiz was garrisoned with about 20 troopers, and they stole some horses, knowing that he would chase them,” says John Hatch, a local resident who occasionally brings tour groups to the site. “They set up this ambush for him, on the road between Galeana and Casas Grandes.”

When Mata Ortiz and his troops realized they’d been trapped, they took to the closest high ground, hoping to dig in until reinforcements arrived. The Apaches, though, surrounded the Mexican forces and slowly picked them off from a distance with their rifles. Of the 23 Mexican soldiers, only two survived the onslaught: an infantryman who was allowed to escape, and Juan Mata Ortiz. “The instructions to all the Apaches were to not kill el capitan,” Hatch says. “So all the others were picked off one by one, but they threw him in the pit and burned him alive.” Over a century later, the hill still bears his name—Cerrito Mata Ortiz.

Today, says Hatch, Geronimo-obsessed tour groups from as far as Germany come to see the site. “When you climb up on the hill, you can find piles of rock that the Mexicans had stacked up to defend themselves,” he says. “Occasionally, people still pick up some old shell casings from the battle.” If you look closely at the top of the hill, you can see a subtle depression in the terrain—the pit where the Apaches exacted revenge their on Mata Ortiz, nearly 130 years ago.

Over at the town of Galeana’s provincial government building, an exhibition of artifacts, including photographs and metal spurs, tells the story of the ambush. The town’s Plaza Juan Mata Ortiz, with a stone memorial, honors the commander.

“After the ambush, when the Apaches came to Galeana, all the people ran to the old church,” Whetten says. “They said that, from up in the bell tower, they could see smoke coming from a fire on that little hill.”