Just a few hours south of Tucson, on the other side of the border, there’s a quiet, dusty Mexican town called Sásabe. The streets are empty, the pavement rutted in places, overcome by the sandy earth in others. Like countless towns along the border, Sásabe feels less like a place where people are born, grow up, live, work, marry and raise children; and more like a way station, a place designed for an itinerant population of migrants and would-be border crossers. Somewhere to rest. A place to buy water and food. A place to consider the journey thus far, and prepare for the trials to come. At midday the heat is blinding. After dark, the desert is cold and unforgiving. There are few shops or restaurants, and no identifiable center of town. Sásabe long ago gave in to the reality of its unfortunate location. Everything feels temporary, and one imagines that the houses themselves could pack up and go, if they were called upon. There’s an image: This cluster of anonymous, dun-colored buildings trudging north across the scrub brush. Of course they would stop at the wall because Sásabe’s defining feature is the border fence, rising to the north, marking the town’s beginning and its unfortunate end.

In fact, the border fence is the only construction in Sásabe that feels remotely permanent.

The offices of Grupo Beta sit on Calle Primera, not far from the border. There’s no number on the building, but you wouldn’t need it in a town this small. I visited there in September 2011, a few days after a rare heavy rain. The desert had responded with a tentative dash of color — a blooming cactus here, a hint of green or red there. It wasn’t much, not renewal exactly, but the suggestion of it; but even so the landscape and its muted palette felt suddenly full of possibility. I mention this because when I think of Grupo Beta, I think of them first as a color. The employees, three of them the day I showed up, wore bright orange jump suits, a vaguely space-age uniform, as if their mission were a dress rehearsal for a trip to a distant planet. There’s something in that, of course, an echo of interstellar travel in their work: Grupo Beta was founded by the Mexican government in the 1990s to help migrants. They provide counsel, aid, refuge. But, as the workers explained to me that day, their primary task isn’t to help migrants cross. Instead, they’d been dropped on this Sonoran moonscape to dissuade them. To tell them: No. It’s not worth it. Turn back and head home. For migrants who accept the advice, Grupo Beta offers subsidized, one-way bus tickets back to their homes.

The centerpiece of the sparsely furnished Grupo Beta office was a map of the Sonoran desert. It included roads and highways, towns along the Arizona border, but this map wasn’t a guide for border crossers. If anything, it was posted there as a warning. The map was dotted with crosses, one for each body that had been found since the office had been opened. There were dozens upon dozens. This was Grupo Beta’s message to the migrants.

Did it work? I asked.

Not really.

Imagine, the Grupo Beta workers told me: You’ve come from El Salvador, or Honduras. Or Chiapas. You’re running from something — crippling poverty, the narcos, the maras and their homicidal violence. Corruption. A broken heart. A failed marriage. Or you’re running toward something: You have family on the other side of that wall, a future that feels so close it no longer requires much imagining. Its shape is visible to you: green lawns and suburban houses, or vast cities dense with women and work and money waiting to be spent. You’ve left your home. You’ve survived The Beast. You’ve been robbed, you’ve been extorted, you’ve been beaten or raped, and you’re here now. You’ve come so far. The finish line is in sight.

Or at least that’s what it feels like.

To those people, the orange-clad workers told me — to these migrants, those crosses in the desert don’t mean anything. They don’t seem real. How do you convince men and women who’ve risked everything and fear nothing that they can’t keep simply walking?

You can’t. But you tell them anyway, knowing that they’ll be on their way at dusk, knowing some of them will end up as crosses to add to the map.

Since 2001, at least 2,600 migrants have died while attempting the perilous crossing from Mexico into Arizona. Each circle in the interactive visualization below corresponds to the known location of someone’s death.

Fatal Migrations - Josh Begley

Interactive: A visualization of migrant deaths in Arizona, 2001-2016. Data courtesy of Humane Borders and Pima County Office of the Medical Examiner.

Josh Begley

Text by Daniel Alarcón. Data visualization by Josh Begley. Alarcón is the author of At Night We Walk in Circles and executive producer of Radio Ambulante. He teaches at Columbia University’s School of Journalism.