It's a four-hour drive from Punta Arenas to Torres del Paine - longer if you stop to smell the llamas on the way. Pink flamingos pass their thick bills through the shallow waters of the salt pans that line the track. You pass plenty of estancias - large working ranches - and motor through some prime trout-fishing country.

The track cuts a straight path for miles across great expanses of scrub and you can imagine the landscape and the blue sky above it stretching forever beyond you.

The mountains of the Parque Nacional Torres del Paine rise suddenly. The 181,000-hectare park is named after these granite towers - named Paine, an Indian word for 'blue' - which jut dramatically from its grasslands.

The park is renowned for its hiking. From September to April it welcomes tens of thousands of trekkers keen to explore its glaciers, marshes, forests, lakes and mountains. Its most popular track is the 'W', a hike that takes about four days. The path is shaped like the letter, zigzagging in and out of the mountains. The first stroke takes you from the dramatic Grey Glacier, where you can see ice from the bright-blue glacier crash into the grey waters of the Lago Grey. The path runs along the eastern shore of the lake, through silent forests and bogs. You snatch glimpses of icebergs making their way through the lake to its southern shore as austral blackbirds and woodpeckers flit through branches.

The path turns back on itself and into French Valley, one of the most beautiful stretches of the hike, winding between Paine Grande on your left, the park's tallest peak, which reaches 3,050 metres to its snowy top, and the base of Los Cuernos (The Horns) on the right, stretching 2,600 metres into the sky.

The strange, two-tone colouring of The Horns and its wild shape both stem from its formation. Hard, light-coloured granite has pushed up the softer, black sedimentary rock that once formed the bottom of the valley. Over the centuries, harsh winds have bitten into the black rock on the top of the granite, causing it to shear away, leaving knife-like peaks.

The path backtracks out of French Valley and heads along the front of Lake Nordenskjold. The third prong of the W leads into the Valle del Silencio, a grey, steep-sided valley that once served as the hideout for a notorious cattle rustler. Overhead, condors wheel through the sky without a sound, their vast black wings allowing them to circle for hours in search of carrion.

At the end of the valley hikers must negotiate a moraine, a boulder field that forms a strange, waterless river of rocks. It leads up to Las Torres (The Towers), three granite peaks that poke above the snow and into the clouds. Below them the treeless rockscape is entirely barren and moon like, with boulders and gravel surrounding an icy green lake.

The bad news for those with weak knees is that the return path leads back down the moraine. The good news for intrepid hikers who have reached the end of the W is that there is an even longer trail, known as the Circuit, that continues around the mountain range. The whole loop takes about nine days to complete.

Although the park is in the deep south, it is surprisingly temperate. Even in the middle of winter, June and July, the mercury rarely dips below freezing. Snow makes it easier to spot the animal life in the park - and visitor numbers drop way down. Yet even though the park's proximity to the sea keeps it relatively warm, you can experience the proverbial four seasons in one day at any time of year. Patagonia is notoriously blustery, so carry warm clothes and windbreakers in your rucksack, even in summer.

The climate is kind enough to sustain a large population of guanaco. These rust-coloured, white-bellied relatives of the llama are skinnier and smaller than their better-known cousins and Torres del Paine is one of the last places where large herds graze on the pampas.

The rhea is another staple of the Patagonian landscape. Known locally as the ?andu, this half-size relative of the ostrich pecks its way through the scrub in small flocks, scurrying nervously away with head held high and feet kicking when approached.

A few wild puma prey on the larger animals in the park, particularly the guanaco, but they are nocturnal hunters; it is far more common to come across the Patagonian grey fox, trotting over the park's hillsides and slopes with a jackal-like skip and jump.

Cabins and campsites along the trail stand ready for hikers willing to rough it a little. These refugios offer bunk beds, kitchen facilities and meals for a few US dollars. One of the most modern hosterias (hotels), the Hosteria Pehoe, represents a considerable improvement in amenities and a considerable leap in price. It has a lovely view from the five-hectare island it occupies in Lake Pehoe and double rooms cost about US$170 a night.

At the top end of the luxury scale is the Hotel Explora. This eco-resort is decked out in lenga and cypress wood and boasts a stunning location: next to the Salto Chico waterfall, at the southern end of Lake Pehoe. On the other side of the picture windows in the restaurant, the Paine Grande and Los Cuernos reach into the sky. A four-night stay starts at US$1,560 a person and includes all meals, drinks and daytime guided trips.

Each day offers a choice of one of 23 different excursions, from easygoing walks to eight-hour hikes.

And there is always the promise of a tangy pisco sour and a few glasses of locally made wine to accompany a meal of sea bass, salmon or steak at the end of the expedition.

But wherever you stay, it is the scenery that is the star attraction. It is almost spiritual in its beauty. This is a land to lose yourself in, to gape at. It is nature at its most majestic, at the end of the Earth.

explora.com for the Hotel Explora.