There are days on a ride that are simply about distance. This was one of them. Today, we would leave the estancia far behind, traveling more than fifty kilometers, carrying with us all that we would need.

The ponchos we’d been given — startlingly heavy, dense — had felt, on our first day, more like costume than equipment, and the whiskey-filled travel flask felt more decorative than useful. But by this morning, we retrieved them with the particular appreciation reserved for things handy to have in demanding conditions — things you tend, like embers banked overnight.

All I knew of Ivan was what I saw at each day’s start, as he tacked the horses up, and each day’s end, when we dismounted and he took over. At first glance, the tack he assembled seemed more like layered bedding than the English dressage saddle or Western working saddle I was used to. First came a white sheepskin, placed fleece-side down against the horse’s back. Next he placed a thick woven wool blanket, like a standard Western saddle pad, then a shaped, lightweight leather saddle, equipped with stirrups and a fleece-faced girth. Over the top of that, Ivan laid a second sheepskin — this time, with the fleece facing up, to cushion the rider. To hold it all together, he wrapped a leather strap entirely around the horse’s barrel, cinching it in place.

Then came a halter of plaited rawhide, a geometry of triangulated shapes; to it, he attached a lead rope of rawhide line, its loose end coiled at the rigging. Over that, he placed the bridle; made also of rawhide, it was stripped to the elements essential to managing the bit — just a head piece, browband, and two cheek pieces. Finally, both in front of and behind the saddle, he slung saddle bags of wool and leather, with rawhide ties for bedrolls or ponchos.

What Ivan carefully assembled each morning is known as the recado. More than a saddle, the recado is better understood by its deeper origin: it descends from recaudar, meaning everything gathered and secured — the full supply of what’s needed for a task.

So, well equipped, we rode out, the day settling into a steady rhythm. I didn’t know the landscape we would encounter or where we would end — “to the caravans” was about all I knew of the course we set. But that morning I began to discover a deeper certainty: that whatever we needed, we already had — and that, like an experienced rider ponying a colt, Marcos would take us safely along. That unspoken agreement set me free, it seemed, with nothing to decide, nothing to track, no reason to worry. Just Marcos in the lead, and the country coming on.

At regular moments along the way, when the ground was especially clear, Marcos would turn in the saddle. The horses knew the turn’s meaning before we did. But soon enough, we knew it, too. With a tilt of his head, he would call out what proved to be his characteristic invitation: “Ready for a canter?”

Whether it was our position in the valley or a bit of magic granted to the day, the wind had stilled. We followed the curves of the shallow river, splashing across whenever the path proposed it. The horses bent their necks to drink. Reflecting back in the river’s clear waters, the sky was as blue as ever I’ve seen. On the ridges above, clusters of guanaco looked down at us, laughing.

Only a few hundred people had crossed this hidden valley over the past hundred years, Marcos explained. All day, what I had noticed was the valley’s beauty, and its silence, broken only by the sound of our quiet voices, just four riders and two guides inhabiting an entire landscape.

But what I hadn’t understood was the source of this silence: we rode the path of the Selk’nam, one of the three indigenous peoples of Tierra del Fuego. Long before the sheep and the fences, before the gauchos and the estancias, this steppe was home to the Selk’nam. For more than 10,000 years, the Selk’nam had occupied the open grasslands of the interior steppe, subsisting as forager-hunters, hunting guanaco and the small rodent they called apen, and building temporary shelters using hides and poles. Yet over the course of just a few decades at the end of the 19th century, they were hunted nearly to extinction.

It started with the gold-seekers. Julius Popper, an engineer turned prospector, led armed expeditions that hunted the Selk'nam outright, clearing the land for unimpeded acquisition. But the gold was never as abundant as the reports suggested. When the gold ran thin, estancieros — large-scale sheep ranchers — moved into the region. The Selk’nam, who had hunted guanaco across that grassland for millennia, began to hunt these sheep in turn. The estancieros, treating this as ready justification to eliminate the people wholesale, hired mercenaries in retaliation. José Menéndez, the largest sheep rancher in Patagonia, employed as foreman a Scottish mercenary named Alexander MacLennan, who paid his men for each Selk’nam ear they delivered.

So this quiet valley had never been just empty; over the course of just a few decades, it had been violently cleared and claimed and taken from those who had made it their home for millennia.

During our ride, I knew none of this history. So when we rode up at dusk to a string of gaucho caravans set along the hillside — a miniature village, made ready for us — I was only tired, glad for food and company and a small space to call my own for the night. Ignorant of the story of the land below, I slept.

It’s a pretty small plane, the one that takes you from Buenos Aires to the far southern tip of South America. And for reasons known only to the invisible algorithms that decide flight routes and frequencies and load, your plane leaves in the middle of the night.

Which means that it’s midnight when you make your way to the airport; in a big city with two airports, this is the little one, located not far outside the city limits but right there, only a mile or so from the Palermo neighborhood. “I could have walked here,” I thought, as I pulled myself from the taxi.

In this puddle-jumper hub, the terminal is easy to navigate; security is quick, baggage check is easy. At 1 AM, the shops are mostly closed, but the place is surprisingly busy. As I settle into a bare-bones seat at the gate’s small waiting area, I start to register the people around me. No business suits here, no click-clack of high heels. Running shoes, hiking boots; gear bags, cases for rods and reels, fleece and all-weather gear; and everybody — everybody — has a backpack. These are people dressed to move.

What I’m looking for, though, is a particular tell: paddock boots, that universal sign of a horseback rider. While it’s true that some rides attract the Western boots crowd, this one — with its long days in and out of the saddle, the varied terrain and the need for the easy on/off of all-weather pants — this one calls for the all-rounder utility of the paddock boot. No rider worth her salt will pack those boots, let alone check them. On a trip where your boots are the irreplaceable essential, it’s safer to keep them on your feet.

So as I wait for the boarding announcement, I play my horse-girl version of Where’s Waldo: I look for the boots, for the people, mostly women, who carry a certain disregard for artifice or decoration — too messy, in the barn, and too easily snagged off — and who move with an easy physicality. I peg one or two in the waiting area before the flight is called.

Once on the little plane, the game continues. As I ear-hustle my way along, I pick up a few more clues, and by the time we land — no air bridge here; we walk down rickety metal steps and across a tarmac to a low-slung building where we all pull bags from the very small carousel and then I’m walking uncertainly in the general direction of the exit, looking for somebody with a van and a sign that says I’ve found the right place — by then, I’ve pegged them and apparently they’ve pegged me. “Come this way; they’re waiting for us over here. You’re riding, right?” And now you’re part of a gaggle, where two more strangers with open smiles and an easy way about them somehow seem to know who you are as they check your name off their list; soon, you find yourself hustled towards a van where someone offers you chocolate and little cups holding something hot, and then you’re trying to notice faces and find a seat and make sure to smile, and you begin to bridge the gap between getting there and being there. And as one of your guides slips behind the wheel, he turns to look over his shoulder with a welcoming nod. “I’m Marcos,” he says, as he pulls from the curb. And it’s then you know for sure: you’re on your way.

At the end of the earth, the wind is something you either confront or accept. You discover this in the first hour — it is not the wind of a storm, which surges and passes, but a constant presence in the sound and shape of this land.

This first day’s ride is short by design — an introduction of horses to riders, riders to landscape, people to one another. As clouds gather and rain begins to spit, the grass grows slick, the terrain a maze of tussock mounds, peat hollows, and hidden marsh. With its slopes and dips, its tangles and divots, this rugged land rewards a steady hand and a balanced seat.

Marcos sets the pace of the gait and the tone for the group: he is amiable and utterly comfortable as both leader and host. Adept with his horse, he makes easy conversation as we move, no doubt silently assessing the riders he guides. Backing him up is seventeen-year-old Jacinto: the latest in his family to take his place on the steppe, he is resplendent in a glorious black cloak whose scarlet lining whips bright in the wind. A gift from his mother, he later confesses.

Neither loamy soil nor hardpacked earth, the tussock is new to me. Bunched into clumps, the deeply rooted grass forms a dense patchwork of isolated mounds, creating an uneven surface that demands careful footfall. My first impulse — to neck-rein my horse across the unfamiliar surface — quickly proves both unnecessary and naïve: true to his Criollo nature, my horse Bayo — like Marcos — moves with insight and ease.

This first ride lasts only a few hours, circling back to the estancia we had first reached only that morning. But by the time we return to the shearing shed, surrendering our ponchos and accepting the whiskey that magically appears, the world has shifted a bit. As we draw up our chairs for dinner around the family table, we’re well past the need for introductions, now.

The day starts with the river. You ride out north from the estancia in southern Argentina, the Río Grande somewhere ahead — a fact of the map before it is a fact of the eye, because this is open country and the land holds its water low. The wind is just as it is, clouds scudding fast across the sun.

We reached the water mid-morning and kept its company for hours. Running slow and gentle between marsh-edged banks, this river is famous out of all proportion to its scale: sea-run trout push up it from the Atlantic, and people cross the world to stand here and cast their lines. Pulling lunch from saddlebags, we ate on a grassy bank and then dozed, unhurried, as the horses grazed nearby. The wind did most of the talking.

Later, as the circle of the day’s ride turned us back toward its start and the light began to slant, Marcos guided us alongside a line of low ridges and hollows in the grass, their edges long since softened — the kind of thing you might take for an old water-work, riding past without a thought. An ordinary scar in the life of a landscape.

But rather than evidence of everyday infrastructure, we learned, these hollows were remnants of military trenches built for a war that almost started, for control of three islands that few can name, and at a price that many have paid.

At heart was a familiar tussle between two nations arguing over a border. In 1881, when the Boundary Treaty established the Beagle Channel as the dividing line between Argentina and Chile, it failed to chart the path the channel took — and so, though its terms gave Chile every island south of the channel, no one could say which islands those were. In practice, the doubt came down to three small islands at the channel’s eastern mouth. For the better part of a century, the two sides squabbled over them, but the stakes stayed small: the three meant kelp, guano, and a lighthouse.

What changed was what nations could do with water. Technologies developed for World War II found new purpose around the world. Sonar built for hunting submarines became fish-finding; and refrigerated factory trawlers carried the far side of the planet’s catch home. Since the 1940s, Argentina had drawn oil from beneath this island to heat a nation of homes that had long relied on wood and coal — and now the derricks were learning to drill the seabed itself. The new law of the sea hurried after the technology, drawing two hundred miles of ownership around every shore: whoever held a rock when the rules locked would hold the water around it forever. So when the two countries carried the question, as they had done before, to arbitration under the British Crown, and the award went to Chile, Argentina’s military dictator refused it — and called up the fleet.

A country at war takes what it can reach, and what Chile could reach was here, this bit of the island. The border between the two nations crosses Tierra del Fuego itself, north to south, just west of this grass. On the Argentine side of it sat Río Grande — the naval air station whose planes would cover the fleet and the landing force at the islands. Knock it out, and the operation to the south would lose its air umbrella. A war between neighbors over three small islands does not end in conquest; it ends at a table, where each side trades what it holds. If Argentina seized the islands, Chile’s strongest counter was not to wrestle over the three small rocks — it was to take the Argentine north of this island: the base, the town, and the oil country — the whole island, then, and the chip to trade against the rocks.

The conscripts were boys: twenty years old, all of them born in 1958 — in the conscription rolls, the clase 1958. Two years earlier, at the door of their service, the army had taken away their identity papers — and without papers, a man could be held for as long as he was needed. Their two years were nearly up; they should have gone home that October. Instead they were held, and sent here, to dig these trenches into the grass between the border and the base. Across the whole frontier that December, three hundred thousand men were mobilized — the largest call-up Argentina made in the twentieth century.

Argentine marines prepared to land on and occupy the three islands at dawn on December 22. But in a place where the weather bows to no man, a storm blew in and pushed the planned invasion aside. In this heavily Catholic land, a messenger sent by the Pope, Cardinal Antonio Samoré, reached Buenos Aires before the plans could be reset. The mediation he began would take six years, and would end just as the arbitration had: the islands went to Chile — agreed to, this time, by a democracy, in a vote where four of every five Argentines chose peace.

When the war failed to arrive on schedule, the conscripts were not sent home; instead, they were held at the border for months, well into the following winter. But after eventually discharging them from duty, Argentina declined to recognize them as military veterans — there had been no war, after all. Decades later, a congressional bill would refer to this as “a situation that no one gave account of.” Even today, men well past their years of military service are asking their country to acknowledge a history it declines to tell. Only later, studying a map at my desk, would I realize where we’d ridden that day: this history was just a stone’s throw away, and we’d traced the border’s invisible path.

We rode the last hour mostly in quiet and came back to the estancia at the blue end of the light. Here, there was fire, and dinner, and the easy noise of people glad to be gathered inside — the long table full, every one of us accounted for. In the morning, we would leave this place and, together, ride south.