Chile's desert is so still, so quiet, a traveller might feel they had entered a vast sensory deprivation chamber. It looks, and sounds, like no place on earth

It has no business raining. This is the highest, driest desert in the world. There are river beds here that dehydrated more than 100,000 years ago and have not seen a drop of water since.

The Atacama is the driest place on the planet – that is the kind of irrefutable truism that nails the vital round in pub quizzes. You can bank on it. But I arrive – and within minutes it begins to rain.

Nothing about the Atacama conforms to one's preconceptions. The vital statistics are impressive – a 600-mile-long strip of land on Chile's Pacific coast. It is 20 million years old, covering more than 40,000 square miles. But it is bigger, grander and infinitely more mysterious than the bald figures suggest.

My guide, Rosa, eases the Land Cruiser off the main Calama–San Pedro highway and we are immediately plunged into an unpeopled and unforgiving terrain. The black earth looks freshly scorched, blue ridges ripple on the horizon and above them is the spectral presence of the sacred volcano Licancabur (19,400ft). The only signs of organic life are clumps of thorny cacti known locally as Cojin de la Suegra – mother-in-law's cushion. They don't make the landscape look any cosier.

At Hierbas Buenas, an island rises in the desert. It is, says Rosa, deep strata rock composed of calcium sulphate, gypsum and ash – soft enough to carve. Ancient herders sheltered here and between 300BC and AD1200 they inscribed petroglyphs into the walls. There is life here, after all – the simple scratched outlines reveal lamas, guanacos, foxes, flamingos, monkeys and a dog.

We descend to a river bed where we find a little green Eden. Donkeys and lamas graze together. The lamas have fluffy tails and gay red ribbons tacked to their ears, which makes them look ornamental and slightly silly. They munch on, regardless.

Eventually, near Matancilla, we pull up in a desolate valley. We are more than 10,000ft above sea level. The sun is vertical and has a laser-like intensity. There is no vegetation, but there is colour. The first ridge is rust-red, and looks at first glance to be the work of super-gregarious termites. Behind it, another larger hump-backed hill is green with a lateral white stripe. Rosa reels off the minerals that give the valley its hallucinatory look– olivine, copper sulphate, white mica, silicate of aluminium, black biotite.

Nothing stirs. The most ephemeral phenomena seem to freeze. The wisp of cloud suspended above the ridge holds its form as if it is etched into the deep blue pane of the sky. It is permanent. And then there is the silence. Even in the most tranquil places, there is usually something that gives your ears some purchase; cow bells in the distance, cicadas, wind noise, the buzzing of flies, running water, the mournful cry of a raptor – something that anchors you to existence. Here – nothing. There is no sound at all. You could hear a pin drop far away in Santiago.

I am in a vast sensory deprivation chamber. I can feel my heart slowing, my blood flow is sluggish, my thoughts are emptied of meaning. It is an epiphany of sorts. Then the breeze picks up again, the cloud slowly turns to vapour. The world is no longer holding its breath.

San Pedro de Atacama, the hub of tourism in the area, is an untidy low-rise affair – dirt tracks and high-density shanty housing on the outskirts soon morph into lanes with high adobe walls behind which a large concentration of luxury hotels are hidden. The treasures of the Atacama are no longer the exclusive hoard of hard-bitten explorers. Despite its remoteness, San Pedro has been transformed over the past 15 years from a provincial market town to one of the "tick box" destinations on the South America trail. There are now five or six hotels that compete for top-end tourist bucks. Despite the occasional water tower or communications mast, they all tend to keep a lowish profile.

The Hotel Awasi only has eight rooms – fashioned out of adobe, stone and wood. It is owned by a Santiago-based architect/designer couple who have shown admirable restraint – carefully weaving in the desert environment with big-city comforts. Adobe brown, sand grey and terracotta tones are complemented by throws and cushions with acid accents. Simple local materials and crafts are used throughout. There is, however, no compromise with the food – warm beef carpaccio and fresh seafood in the Chilean outback come as a pleasant surprise.

Despite its newly acquired cosmopolitanism, the centre of San Pedro retains the feel of a frontier town. The main square has all the requisites of a spaghetti western; the stucco-fronted municipalidad with its dark arcade begs to conceal a posse of bad-guy sharpshooters. Across the road, the simple whitewashed colonial church and bell tower seem poised for the incipient showdown. Any minute now, the Man With No Name will drift into town – cigarillo dangling from lips – presaging something bad.

Modern drifters are more likely to come packing rucksacks and ride in on 4WDs. They are readily found at the Adobe Bar – which has a generic affinity with similar boho hangouts in Bali, Kathmandu or San Cristobal de las Casas in Chiapas, Mexico.

The bar is in a courtyard, the central area of which is open to the sky – a large bonfire fed with scrap wood is roaring away in a brazier. The chatter is polyglot. The playlist is backpacker international – Dee Lite's "Groove is in the Heart", The Clash's "Should I Stay or Should I Go", Stereo MCs and Iggy's "Passenger" follow in quick succession. We are, ethnologically speaking, a bus ride away from The Fridge in Brixton circa 1989.

Then the electricity cuts out. The stars are more vivid in the cold, black sky without the light pollution of San Pedro. Happier, louder conversations fill the holes left by the absent thump of the sound system. Maybe we have inched a little closer to our real geography 8,000ft up in the Atacama.

The next morning, we start early for a picnic at around 15,000ft. We head south-east past the snow-covered flanks of the omnipresent Licancabur towards the Jama Pass (13,800ft) that marks the border with Argentina. The volcano has been a brooding presence in every view since I got here, and it becomes more commanding the nearer we get. Behind it another great flat-topped volcano, Juriques (18,800ft), is revealed. The shapes are geometric in their simplicity, upturned snow cones against a graduated blue that merges with space.

The highway levels off on the plateau and takes an unnervingly straight line until it seems to disappear into the folds of the earth. We come to the first of our lakes. The air is crisp, clean and thin. Orange-eyed crested ducks paddle, while a herd of vicuña graze in the shallows. They seem very easy-going when I walk up to them – maintaining a flight distance but refusing to panic. At this altitude, I suspect the threat would have to be palpable before an animal might consider expending energy on a speedy getaway.

The next lake is another step into the improbable. Salt deposits along the shoreline give off an unearthly white glow, while the water grades from lime green to olive and then intense turquoise. Two or three horned coots float on the surface, the only sign of life in the mineral terrain.

Ever higher we go. At the salt lake Salar de Pujsa (14,400ft) I get out of the Land Cruiser to gawp at the faux- Arctic view – the ice floes on the lake are, in fact, encrusted salt. Flamingos tiptoe daintily in the water dredging for food. I wonder what they live on? Salt and air (served very rare)? I make my way down the hill to the edge of the lake to get a better view, but this entails a scramble back up the slope. Soon, I am breathing heavily. My heart is pounding. With every exhalation, the air from my lungs escapes but it makes no attempt at all to return – my body has lost the reflex that reminds it to inhale.

On our way to the Salar de Tara, I stop to get a photo of some extraordinary rock formations. Huge towers of rocks have formed in the shape of two fingers giving a colossal V sign to the western Cordillera of the Andes. I line up the shot and as I am looking through the viewfinder, the sky starts to tip downwards – seconds later I realise that Iam tipping backwards, about to lose my footing and my consciousness. I crouch down fighting the waves of dizziness.

We finally make it to the lunch spot where, under a cathedral-like cliff face, Rosa and the driver lay out a formal picnic table complete with surreal gingham tablecloth. The hamper contains a full three-course lunch, various condiments, sets of cutlery and a bottle of chilled Chilean chardonnay. The view between the escarpments is primordial, empty, huge – but not as huge as my grin when I pose for a picture, wine glass in hand. I am, of course, high as a kite.

How to get there

Sankha Guha travelled to Chile as a guest of Audley Travel (01993- 838640; A 10-day trip, including three nights in the Hotel Awasi, starts at £3,450 per person, based on two sharing and including international and domestic return flights, accommodation with all meals and excursions at Awasi, and B&B accommodation elsewhere.