THE border - or, at least, the gullies, chasms, ledges and high-wire ridges that define it - is roughly discernible, even at 36,000ft. I know this, because the pilot states the obvious.
"We are about to fly over the Andes," comes the voice on the public address system, a note of warning to its low drawl. "Please fasten your seat-belts."
And there it is beneath the wing - the mountain range that supplies a near-literal spine to South America's rainforested back. And with it, almost instantly, comes the rage.
The turbulence that buffets the aircraft as it enters the Andean realm is like nothing I have felt in any Atlantic tantrum or tropical hab-dab - the suddenly fragile plane shivering and bouncing as it struggles with the thermals. But even viewed through a window that might be the door to a washing machine (and I the clothes swirling within), the picture is clear - the peaks below a child's school-drawing impression of how mountains should be, snowy and pointed, an elongated Christmas cake given too much icing. And at this altitude and southerly latitude - where the Andes are narrower - I can see both sides, the Argentinian plateau a stubborn green behind, the dark patches where Chile slopes to the ocean ahead.
Few nations are shaped by their physical limits quite like Chile. The day after I arrive, Andres Garrido - while guiding me around the capital Santiago - reads to me a little local wisdom. Scrawled in a dog-eared book, it is one of those slices of well-thumbed folklore of forgotten origin. But as a summary of the country, it works. "When God created the world," it runs, "he had a handful of everything left - mountains, deserts, lakes, glaciers - and he put it all in his pocket. But there was a hole in his pocket, you see, and as he walked across heaven it all trickled out, and the long trail it made on the earth was Chile."
Chile is just such a place: 2,800 miles in length, yet on average just 109 miles wide (and only 265 miles across at its thickest point) - a tapering ribbon of a country pinned into place by the Andes on one side and the rolling bulk of the Pacific on the other. And with this, it is home to stark geographical diversity, its upper corners a desert wasteland, its midriff grassy and fertile, its southern tip (where Cape Horn jabs at Antarctica) a frost-glazed outpost.
Certainly, it is easy to make a case for Chile as the final frontier - the flicky tail of South America, veiled behind a rocky curtain. Perhaps this explains why it only appears on our radars in moments of disaster: the 8.8-magnitude earthquake that violently assaulted the country in February 2010; then, in August, the mine collapse and rescue mission that danced across TV screens last year.
True, in travel terms, it is not an entirely unknown quantity - the glaciers, fjords and raw majesty of Patagonia have lit up many a holiday brochure. But on a continent where Rio is awash with travellers, Buenos Aires revels in its tango-and-T-bone image and Machu Picchu receives up to 2,500 visitors per day, Chile is still the quiet child at the foot of the stairs.
So when I land in Santiago - almost at the centre of the country - I am keen to peer into this less-observed looking glass. And not at the chill beauty of the jagged south - but at the true, populated Chile that vibrates in the capital, or scratches a living in its arid north.
Garrido greets me with a bike and a grin. The founder of guiding company Paseos En Bicicleta, he knows Santiago well, and leads me to Santa LucIa hill, the spot where the city first drew breath. A steep bluff of 227 feet that feels all the steeper by pedal, it was here in February 1541 that the Spanish conquistador Pedro de Valdivia - noting that the hill could be defended against the indigenous Picunche people-planted his banner.
Half a millennium on, a metropolis spreads about it, ebbing towards the Andean wall that you cannot escape - a constant presence in your eye-line. Valdivia has not escaped either. A vicious man who would end up executed by the Mapuche tribe in what is now southern Chile, he glares across the Plaza de Armas - captured in bronze on horseback, just one of the echoes of colonial Spain that sound in Santiago. Nearby, the Plaza de la ConstituciU* recalls the pomp of an empire that overran a continent - while the Palacio de la Moneda, a 1786 pile that was once the Mint, still projects power as seat of the Chilean president.
But elsewhere there is a sense of a city that has developed as part of a game of Chinese Whispers, the fruit of whatever distant influences seeped through the gaps in the Andes. The Museo Chileno de Arte Precolombino remembers the world before the Spanish - in carved Mapuche grave markers and 7,000-year-old Chinchorro mummies, buried in the Atacama Desert 2,000 years before Egypt perfected the technique. In contrast, the Museo Nacional de Bellas Artes - a showcase for Chilean art - wants to be in Paris, its Beaux-Arts shell concocted in 1910 when Santiago's planners were in thrall to all things French.
And when Garrido leads me into the Lastarria district, another Santiago emerges - that faded yet decadent South America of the early 20th century, with restaurants and bars injected into what were once grand homes. The house that holds Cafe Berri is shabby and frayed, but it must have been magnificent, all creaking wooden floors and ornate ceiling-high mirrors.
True, there are also recognisable slashes of modernity: the swish restaurants in affluent Vitacura, east of the centre, where Puerto Fuy serves up a sprightly merluza (hake) with ratatouille for 12,000 Chilean pesos ($AU23); the Bellavista district, with its late-night bars and chic retreat The Aubrey - a boutique hotel (and my base for three nights) where 15 rooms have been lovingly slotted into what, in 2006, was a semi-ruined Spanish mansion.
But there are also dabs of the truly unusual. At the end of our tour, Garrido and I halt at Cafe Haiti, a coffee shop that specialises in the Chilean phenomenon of cafe con piernas. The piernas (legs) belong to waitresses who, all short skirts and stockings, are there to provide titillation as well as cappucinos. The whiff of machismo is hard to avoid, but there is also a hint of the gleefully idiosyncratic. Garrido shrugs. "It's how Chilean men like to drink coffee."
Where there is lasciviousness, there is also literature. On a hill above Bellavista, La Chascona was the home of Chilean poet Pablo Neruda and his third wife Matilde Urrutia. A mish-mash with a nautical theme, it gives a vivid account of a man whose work won the Nobel Prize for Literature in 1971. The trinket gleams in a cabinet in his library. Yet most of his books are gone, burned when Augusto Pinochet's coup d'Etat tore through Santiago in September 1973. Perhaps this is the reason for the capital's indefinable vibe. Military rule is a stain on living memory (Pinochet only stepped down in 1990). At times, Santiago has the unsure attitude of a teenager expecting his Saturday-night privileges to be revoked.
If Pinochet's ghost still hangs in the background, so does Neruda's. After four days in Santiago, I journey 80 miles west to Chile's most romantic dot on the map - ValparaIso.
The poet also had a home here - La Sebastiana, another quirky hillside pad. Staring out of its living-room window - alongside which Neruda's favourite armchair is still planted, flecks of his trademark green ink splashed onto the adjacent footrest - I can see why.
Clinging precariously to a gradient entirely unsuited to urban construction, ValparaIso is a nest of colour and chaos: 42 hills in total; brightly painted houses wobbling on the lip of the abyss; thin streets inching upwards, cars grumbling and coughing in perennial second gear; the Pacific lying below, oddly unruffled, apparently indifferent to the whole scene.
If ValparaIso were a movie cliche, it would be a vampire - dead, and yet alive. Its demise came in 1914 when the opening of the Panama Canal deprived it of both Europe-bound ships and its raison d'Itre. Yet it has settled into a pretty afterlife. A pair of antique cable elevators, relics of 1883 and 1903 respectively, clank up their rusty paths; craft shops and galleries are clustered on Calle Lautaro Rosas; Paseo Atkinson throws out a widescreen view of the port; and restaurant La ConcepciU* does deep-sea grouper risotto in blueberry sauce for 13,000 pesos ($AU25) - on a veranda where the ocean breeze tugs at your napkin.
Beyond, a more contemporary Chile gnaws at ValparaIso's tattered hemline. To the south, leafy vineyards, symbols of the blooming concern that is the nation's wine trade, tout their wares in long furrows - while bodegas such as Matetic Vineyards offer tours of their cutting-edge facilities. To the north, the next-door city of ViOa del Mar basks in the sun as a popular resort, all seafront apartments and casinos for Santiago weekenders - while also casting a backwards glance in the Museo Fonck, an archaeological museum where the inimitable form of a statue from Easter Island, Chile's Pacific outcrop, waits outside.
It would be easy to tarry here. But my journey calls me from the verdant green of central Chile to the red and brown of its north. Emerging from the airport in the parched town of Calama, I discover that the Atacama Desert could belong to another universe. Dust - orange and insistent - sticks to my shoes and trousers, and the Andes are menacingly close, dominating the horizon with brute majesty.
This desiccated landscape seems to stretch on endlessly. But just outside the baked-stone village of San Pedro de Atacama, the Tierra Atacama Hotel keeps its counsel in a mini oasis: 32 rooms, a spa, a gourmet restaurant - a totem of luxury in this ruddy wilderness.
And a rare one in an area where life flows in the past tense. On a crag above, a fortress broods. Built to protect the oasis by the Licanantay tribe in the 12th century, it is proof that existence here has always been tough, its ramparts having, over the years, been asked to repel attacks from marauding Incas and invading Spaniards.
There are other shards of history too: Tulor, the oldest archaeological site in Chile, where the remnants of mud-brick homes date to the 8th century BC; ancient petroglyphs, etched into clay by the Calima people, telling 1,500-year-old tales of animal sacrifice and human endeavour. Elsewhere, Toconao and San Pedro de Atacama pledge their allegiance to 16th-century Spain, squat churches in whitewashed squares, bells pealing in tribute to Madrid.
But it is the area's geological wonder that dazzles. Excursions run by the Tierra Atacama pitch me into Valle de la Luna. Moon Valley is aptly named in its pale otherworldliness, pillars of salt are all that grow here. Valle del Arcoiris (Rainbow Valley) is just as well-titled, its heavy flanks a chorus-line of cobalt, gypsum and lamprophyre, high-kicking between green and pink. And then there is Valle de la Muerte (Death Valley) an unforgiving scar of cracked earth - but one that broadcasts the most photogenic sunset I have ever seen.
Just beyond, Licancabur stands giant guard. This 19,423ft beast is another refugee from an infantile sketch pad, the very stereotype of a volcano - colossal, conical, threatening. Even minus a puff of smoke from its summit, it is evidence of the wild, outlandish nature of this country. And also evidence, perhaps, of a careless deity. Because if God really did drop this lava-fried behemoth from his pocket, you might think he would have noticed.
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