That anyone would starve themselves for a station might strike you as odd. It did me - until I saw the station and its attached hotel. It is about ten times the size of St Pancras in London. Canfranc is perhaps the most spectacular, most ignored and most bizarre white elephant in Europe. The Millennium Dome at Greenwich cannot hold a candle to this blazing example of misplaced optimism, political pomp and official misjudgment. Shelley in his imagined discovery of the ruined statue of Ozymandias would have revelled in this Pyrenean reality. As I stood gasping at this monument to broken dreams I experienced - as would any traveller in this foreign land - an Ozymandian moment.

Canfranc: Station buildings and railway yards against its Pyrenean backdrop

Whispered around the domes and state rooms of the station hotel, the rotting platforms and the marbled Customs halls, are the words: "Look on my works, ye mighty, and despair!" They come from the shades of Alfonso XIII, once King of Spain, and Gaston Doumergue, once President of France. Prime ministers, chief executives and presidents of the European Union should cock their ears and listen.

Canfranc: Inaugural opening 18 July 1928 with the King of Spain Alphonse XIII and Gaston Doumergue President of France

King Alfonso and the French President opened Canfranc International station in 1928, the culmination of 40 years of planning and labour. The boring of a five-mile tunnel through solid rock beneath the Pyrenean ridge which separates France and Spain, 23 further tunnels and three viaducts, and an international treaty (still in force) requiring both parties to maintain the railway, finally took shape in steel rails and wooden sleepers.

So grand a construction project, and so lofty a political metaphor, demanded a station to match. There was no space in the valley on the French side, and it was decided to locate the project in the narrow, dark, valley at the Spanish entrance to the tunnel, near the little village of Canfranc, at an altitude of just under 4,000 ft. Vertiginous wooded slopes and snowy peaks more than twice that height tower above, and a river rushes down the valley. A mile of the river had to be redug in a straight line, and the whole valley blasted and excavated to protect the station from avalanches and rockfalls.

Canfranc: work in progress, 1923

Harried but never interrupted by the outbreak of the First World War the work continued until, a decade after the Treaty of Versailles, the grand projet was ready to be blessed by a King and a President. No more than the marmots shrieking from the rocks, or the eagles soaring above, did these proud human beings know that 1928 was the midpoint between two world wars, the edge of the Great Depression or the brink of the Spanish Civil War. All they knew was that the line that this station served was a triumph of state-of-the-art engineering; the station and its hotel without question the finest in Europe. The King and the President had inaugurated a postwar monument to the optimism of the free association of Europe's nation states.

Canfranc: work completed, 1928

I have just spent an afternoon clambering through wreckage. I arrived on the little one-car diesel train from Zaragoza, whose twice-daily service is all that remains of the dream. The tunnel is closed and the tracks on the French side are rusting away. The station and its hotel are at the end of the line, in more senses than one.

Imagine two platforms long enough for three full-length trains, and between them a three-storey building longer than the Palace of Westminster built in carved stone in the style of a late French chateau, with a high, slate roof crowned by three domes, one at each end and one in the middle. Each facade boasts 75 windows. The building is reached through tunnels beneath the rails, down staircases with white marble balustrades. The high-ceiling hotel reception is breathtaking, a grand flight of stairs sweeps up to the floors above.

The eastern platform, its ornate roof supported on decorated iron pillars and illuminated by thoroughly modern electric lighting, was for French trains, on French-gauge rails. The identical western platform was for Spanish trains on their outsize gauge. Above both hangs the station sign, Canfranc, in Art Nouveau lettering. The two cathedral-like Customs and immigration halls are identical. Passengers waited at mahogany counters with wooden rails on which their suitcases could be inspected.

Marble crests bear the arms of the Kingdom of Spain and the Republic of France. The ornate ceilings are faced in pressed zinc - a new material, all the rage in 1928.

Canfranc: Spanish royal coat of arms

Canfranc: crest of the French Third Republic

Canfranc: the customs hall

Here during the Second World War lines of anxious Jewish refugees from France would have stood, their lives in the immigration officers' hands. There was huge traffic, acknowledged and unacknowledged, between the two countries during the war. That this was the only time when Canfranc really worked as a station adds to the melancholy now.

View from Canfranc: the mouth of the railway tunnel beneath the Pyrenees to Pau in France, closed since 1970

For the station and its hotel are in ruins. Politicians and engineers, their heads full of uncommercial dreams, had miscalculated, and fate intervened cruelly. Traffic through it never took off, the French were never as committed as the Spanish, and in 1970 an 'accident', in which a small freight train on the French side came off the rails and destroyed a major bridge, closed the line through France. France has never got round to reopening it. Spain keeps its end of the line running (just) out of sheer pique, I suspect.

View from Canfranc: line to Saragossa, Aragon

Canfranc - Saragossa train in the platform

There are holes in the roof of the hotel, and every year the snow opens them wider. Only the beat of pigeons' wings disturbs the silence of the Customs halls and hotel reception. You can prise your way past the security fencing and see for yourself. It is like diving the Titanic. The clock has stopped at ten past two. Plaster roses are peeling from the walls, carved stone is flaking, floors are sagging, tiles have slipped.

Canfranc: stucco detailing crumbles from the walls

A train of wooden carriages stands abandoned on the rails outside, columbine growing around the carriage doors and windows.

Canfranc: abandoned train

Canfranc: abandoned freight wagon with bicycle

Canfranc: steel roof

In Britain, perhaps, a lottery grant or a BBC restoration programme might save such a place. I reckon the roof could be secured for about half a million pounds, but restoring what is beneath it would run into tens of millions. Similar sums are being ploughed into new ski-stations and ghastly alpine-style condominiums in the Aragonese Pyrenees, but nobody can find the money to save Canfranc. Besides, what would you do with it? Do we really need a hotel the size of the Victoria and Albert Museum, decorated in the modernist style, deep in a valley in the central Pyrenees? I sympathise with the hunger-strikers but understand the reasons for official paralysis as the station falls down.

Canfranc: ornate period detailing

Canfranc: French chateau-style station buildings in an industrial ruin

More than that, though, I look at the optimism and self-confidence which once breathed through this impending ruin, and ask myself which of the grands projets of our era may face the same fate. Canfranc is all about sovereignty and borders. Neither Alfonso nor Gaston doubted that these would be for ever, and the station embodies that certainty.

The new European nostrum, the nostrum of our age, is all about union and the dissolution of borders. Will the Berlaymont in Brussels, the European Parliament in Strasbourg and Brussels - will, indeed, the European Central Bank and its brave new currency - live up to its dreamers' confidence? Let us not listen too hard for the beat of pigeons' wings, or we shall achieve nothing. But if you want to stand for a moment in shuddering contemplation of the mortality of international dreams, come to Canfranc.

For further information and pictures on Canfranc, see:

The Canfranc Project

La gare internationale de Canfranc

Gare de Canfranc

Pau-Canfranc