The Atacama

Look east from the salt basin and the skyline is a wall of volcanoes. Colachi is one of them, a high cone rising from the same volcanic chain that rings this basin. This matters because the whole desert is built from what mountains like this one erupted — the pale, hard rock underfoot everywhere below, from the valley floors to the ridgelines, is old lava and ash from the Andean volcanoes, laid down over the long last stretch of geologic time and, in places, only recently cooled. What makes Colachi worth finding is not that it is unusual but that it is honest: with almost no rain to wear it down, the cone keeps close to the clean lines it had when it was built. A volcano this age in a wet country would be softened, gullied, and hidden under green. Here it stands as its own diagram. Reaching the summit is a serious high-altitude undertaking; most readers will simply read this peak off the desert floor, as one clear page in a long row of them, which is more than enough.

High on the open plateau north of the salt basin, Cerro Chajnantor rises over some of the driest, highest ground in the desert. The rock is the same volcanic stone that built the whole region, but the reason to make for this ground is what happens overhead. Air this high holds little moisture and little haze, and the empty desert below throws almost no light of its own into the night. On a clear, moonless night the sky here goes deeply dark, and the stars hold steady rather than swimming the way they do through thicker, wetter air. By day the ground itself is the lesson: no soil, no shrubs, just rock and gravel and the long, uninterrupted views that only bare country allows. Nothing softens the distance, so the mountains read sharp and close even when they are far. This is expedition terrain — thin air, hard cold, real distance — and it pays back patience rather than speed. Come with time, layers, and a plan for the altitude.

Out on the great salt flat, the crust opens into pools of vivid blue-green water, and Laguna Cejar is one of them. This is the salt flat’s own logic on plain display: over a very long time, water gathered in this basin, found no way out to the sea, and left behind everything it carried as the sun drew the water back into the air. What stays is salt, more and more of it, concentrated in the water and crusted white along every edge. Around the pool the salt builds into brittle ridges that crack and crunch underfoot. This is a lake caught partway through the long process that ends as a dry pan. Handle the crust gently; it breaks easily and takes a long time to rebuild.

This viewpoint opens onto the salt flat itself — the pale, crusted floor left where standing water dried away. From a distance it reads as an off-white plain running out to the foot of the volcanoes; up close it is a rough crust of salt, buckled into ridges and knobs that turn an ankle. Almost nothing grows, because salt this concentrated is a hard place to make a living. What you are looking at is the end state of the desert’s water: rain and snowmelt off the high volcanoes runs down into this basin, which has no outlet to the sea, and leaves its salt behind when the sun takes the water back up. The mountains give, the sun takes, and the salt simply stays. Of all the open pages in this desert, the salt flat is one of the plainest — the whole story of where the water went, written flat across the ground for anyone standing here to read.

High above the salt flat, in a bowl among the volcanoes, sits a blue lake shaped like an arrowhead. Laguna Miscanti has no river running into it and none running out; it is fed and drained through the ground itself, by springs and slow seepage, holding its level in a place where almost no rain falls. The water is brackish — part salt already, on its long, slow way toward becoming the kind of dry pan you find down on the basin floor. What makes this a page worth reading is the wall to the south. A tongue of old lava runs between Miscanti and its smaller neighbor, a single flow that came down and split what had been one basin into two separate lakes. Flamingos work the shallows, sifting the brine, and on the dry slopes around the water vicuña come down to drink. It is the whole desert in one view: young volcanic rock, standing water going slowly to salt, and the handful of animals that make a living at its edge.

Just south of the arrowhead lake, across the wall of old lava, lies its smaller twin. Miñiques and Miscanti were once a single body of water; then a flow of lava came down between them and divided the basin, and the two have sat apart ever since. Two lakes now sit where the land might have held one, kept separate by a low ridge of cooled rock. This is deep time made simple enough to take in over an afternoon — a single event, one eruption, rearranging a whole landscape, and the result still lying there in plain view for you to walk up to. The bowl is high, cold, and thin-aired, ringed by volcanoes and very quiet. Standing water is rare in this desert; here it comes doubled, and the reason for the doubling is written plainly in the dark ridge between the two shores.

West of the oasis town, a low range of ridges and hollows has been stripped down to bare, folded rock and salt. The valley reads as raw ground — no plants, no soil, only stone, white salt seams, and the shapes that weather leaves behind. In most of the world, ground like this is quickly softened by rain and hidden under a skin of green. Here it stays open, and what does the shaping is wind, and the slow work of salt crystals prying the rock apart grain by grain, in a place where liquid water almost never falls. The result is a terrain of sharp crests, deep hollows, and pale crusted seams you can walk among and read directly, with nothing grown over to hide it. Late in the day the low sun rakes sideways across the ridges and every fold throws its own long shadow, and the shape of the ground comes clear all at once.

A short way from the moon valley, another stretch of bare ground turns red. Valle de Marte is a run of ridges and a broad dune where the rock and sand carry a rust-red color, the ground stripped down and left open the way everything is in this desert. With no plants to hold it in place and no rain to pack it down, the loose surface here is at the mercy of the wind — sand climbs the slopes into dunes and slides back down them, and the bare ridgelines stay hard-edged against the sky. It is about as plain a demonstration as the desert offers of how a landscape behaves once you take away water and greenery and leave only rock, sand, sun, and moving air. Come toward the end of the day, when the low light deepens the red and the dune’s long shadow spills across the valley floor and the whole slope seems to lean.

Almost everything in this note is about bareness — rock left open because nothing grows across it to hide it. This ravine is the exception that explains the rule. Where a thread of water works its way to the surface, green crowds in: a ribbon of trees and brush following the water down a narrow gorge cut into the dry hills, startling against the bare rock on either side. The lesson is the same one the open desert teaches, only seen from the other face of it — here, life reaches exactly as far as the water reaches and stops hard at its edge, with nothing in between. Where the water runs, the ravine is close, shaded, and alive; a step up the bank, and you are back in bare, silent stone. It is a small place, and the whole rule of the desert is legible in the few steps between its two sides.