You have seen the photograph. One figure alone on a sheet of water, the sky doubled perfectly beneath them, the same clouds above and below and no line where the ground begins. It is the image that sells Bolivia to the world, and I went partly to find out whether it was real or just a wide lens and a lucky thirty seconds. It is real. On my last morning I walked out onto the flooded flat before sunrise, and within a hundred metres the horizon was gone, the clouds over my head and under my feet, and the thin film of water I stood in had stopped being water and become a mirror the size of a country. People a little way off looked like they were hanging in the air. It is the most disorienting beautiful thing I have ever stood in, and it is, technically, a puddle on a salt flat.
The Salar de Uyuni is the largest salt flat on the planet, ten and a half thousand square kilometres of it, the ghost of a prehistoric lake that dried and left a crust of salt metres thick. It is so vast and so level, less than a metre of height across its whole width, that satellites use it to calibrate their instruments. For most of the year it is a blinding white plain, hard as a road, cracked into a honeycomb of hexagons that runs to the horizon. Then, from about December, the rain comes and lays a few centimetres of water over everything like a sheet of glass. That is the mirror, and its window is narrow: the wet months, a still morning, the half hour after dawn before the wind gets up and stirs the glass back into water. Come at the wrong time, or on a windy day, and the famous reflection simply is not there. Most people who leave let down came for that one photograph and could not forgive the sky for the weather.
You do not fly to the middle of the altiplano to stand on a puddle for half an hour and go home, either. For most travellers the flat is the last act of something much larger: a three-day crossing by four-wheel drive between Uyuni and the Chilean border at San Pedro de Atacama, most of it above four thousand metres, through country that looks like nowhere else on earth. Those days run through lagoons stained rust-red and jade-green by their minerals, flamingos feeding in water that sits below freezing, the geysers of Sol de Mañana boiling at first light, a hot spring you lower yourself into with your breath smoking, and a bare desert Dalí could have signed. The salt flat is the finale. I came into it that way, after three days of thin air and hard colour, and the plain white of it was almost a relief.
It all begins in Uyuni, and Uyuni is not the reward. The town sits at nearly three thousand seven hundred metres, cold and dust-blown and built around a single industry, every second doorway selling the same tour as the last. There is no charm being kept from you, no old quarter, no nightlife, not much reason to be there beyond the one that brought you. You arrive short of breath, give the altitude a day, sleep badly, and leave. Nobody falls for Uyuni. On the way out the jeeps pull up at a cemetery of steam locomotives left to rust in the desert since the mines they served gave out, and everyone climbs on them in the cold, and that, honestly, is the best the town itself has to offer.
There is another version of this place that I did not get. In the dry months the drivers make straight across the hard crust to Incahuasi, an island of fossil coral in the dead centre of the white, furred with giant cacti that have stood here for centuries, some of them ten metres tall. By every account, from the top there is nothing in any direction but salt to the curve of the earth. I traded that for the mirror, because the water that doubles the sky also drowns the tracks out to the island. You get one face or the other, and you choose before you book. I do not regret the water. But I understand the people who come for the cacti and the honeycomb instead, and I understand them best on a windy morning when the mirror never comes.
The sky is above you and the sky is below you, and you cannot tell which way is up.
The water does more than double the clouds. On my last night the wind fell away and the flat lay dead still, and the Milky Way came out over it and under it at the same time, so that I stood in the middle of the galaxy with no up and no down at all. There are darker skies on earth. There is nowhere else I know that hands them to you twice, once over your head and once beneath your boots.
So does it live up to the photograph? The photograph undersells it and oversells it at once. It undersells the scale, the silence, the clean cold strangeness of standing where the ground has become the sky. It oversells the certainty, because that flawless reflection is thirty minutes of luck inside a narrow season, not a thing you can book. Come for the crossing and the altiplano, treat a perfect mirror as a gift rather than a guarantee, and you will not leave short-changed. Go out at sunrise, when the water is stillest. Bring sunglasses, because the dry flat is genuinely blinding, and shoes you do not love, because the salt eats them. Take the altitude seriously, and reserve your bed in Uyuni before you come. Then walk out far enough that you can no longer hear the jeeps, stand still in the place where the sky is the ground, and let yourself lose which way is up. That half hour is the whole reason to come, and it is enough.
