Flying without wings

It's a true wonder: higher than the Eiffel Tower - and a bit of motorway that makes you want to turn round and do it again, says Ruth Brandon

MOTORWAYS AND pleasure are two words not normally uttered in the same breath. Motorways are about getting somewhere fast, and when that fails, which it usually does, these car-crammed days, they are about rage.

But France has just acquired a motorway which is not only a delightful drive but which promises to become a tourist destination in itself. The A75 between Clermont-Ferrand and Montpellier is the last link in the chain connecting Paris with Barcelona; and the completion of the mind-blowing Millau viaduct means that it is now ready for use.

Millau is situated on the great limestone plateau that forms the southern edge of France's Massif Central, an area whose grand but unrelenting scenery has historically defined the country's communications network. France's main roads traditionally followed its great rivers, such as the Rhone, from north to south. If you needed to travel from east to west, it was rarely possible to do so directly. Other routes might seem quicker as the crow flies but, as anyone who tried them could tell you, those were mighty slow crows. If you wanted to drive from Paris to the south-west Mediterranean coast, you had either to take a long detour to the east, via the Rhone valley, or to the west via the Loire. There was a direct road, the N9, but its precipitous route meant lots of scenic curves and bottlenecks, especially where it met the great east-west river-gorges. Millau sits on the most formidable of these, the spectacular Tarn gorge: amazingly beautiful but a road engineer's nightmare.

The old road crossed the river on a bridge in the centre of town, then snaked its way up the other side of the valley to the Larzac plateau. But it was decided that the new motorway would leap directly from one side of the gorge to the other.

The resulting bridge, designed by Norman Foster, is two-and-a-half kilometres long and (at its highest point) 270m above the valley floor. This makes it the highest bridge in the world - higher even than the Eiffel Tower. (As it happens, Eiffel designed France's hitherto most spectacular bridge, the Garabit viaduct, which spans the Truyere Gorge, 140m farther up the N9/A75. And Eiffel Construction was also a co-contractor on the Millau viaduct.)

Foster is, of course, an architect rather than an engineer. But as he points out, when you build a huge edifice in a position like this, looks matter. His viaduct, like Garabit, is both an engineering tour de force and a work of great beauty. It is supported on seven slender concrete columns, each of which splits into two below the roadway, making them lighter both visually and in terms of materials. The roadway itself is made of steel, for lightness, and is suspended from steel pylons 90m high. It was constructed in sections, which were pushed out gradually across the valley from each side, until the terrifying day when they met in the middle - to everyone's great relief, perfectly. Then the metal pylons were rolled in, brought onto the bridge by gigantic transporters, before being hauled upright, each one sitting directly upon a column. Last of all, the suspension cables were put in place. The engineers have guaranteed the resulting construction for 120 years.

Foster has said that he wanted to make drivers feel as though they were flying across the valley. You don't actually feel like that: although the barriers on each side are translucent, they block the immediate view - and, anyway, you're looking straight ahead most of the time.

You get the effect better if you're a passenger. If there are two of you, it would be worth taking turns. Crossing the bridge off-season costs Û4.57 (in July and August this rises to Û6) - a small price to pay for such a sublime experience, even if you do it twice. But although driving across the bridge is wonderful, its true impact comes when it is viewed from a distance. Then, it really does look as though it's flying across the valley - so light that it seems almost ethereal.

For the moment, the A75 - viaduct apart - is free between Clermont-Ferrand and Montpellier. The idea is to attract people onto it, get them used to it, then start charging. But whether it will ever wholly replace the eastern route down the Rhone valley seems dubious, at least in winter. The Massif Central is very high - 1,200m as you approach Garabit - and the weather can be severe. On the day we went, it was sunny, though very cold, at Montpellier and Millau. But as we climbed higher, snow began to fall, and eventually driving became so unpleasant that we turned back. By that point (about 100km north of Millau), only one carriageway of the autoroute was clear, despite copious salting and gritting.

For tourists, of course, this is unlikely to be a problem. For one thing, they will probably visit in the summer; for another, the ride from Montpellier to Millau, across the great limestone causses, home to the sheep whose milk makes Roquefort cheese, is stunning at any time of year; and once they've seen the viaduct they can turn round and go back again.

It seems clear that the Millau viaduct will become a wonder of the world, one of those constructions, like Frank Gehry's Guggenheim Museum in Bilbao, that people visit for their own sakes, and only incidentally because they want to see what's inside them - or, in this case, where they take you. This is certainly what Millau's tourist office anticipates: the visitor centre is already up and running, offering views of the bridge, lashings of statistics and a film of the work as it spectacularly progressed, complete with a breathless French commentary. (Don't worry if you don't speak French - you're not missing much, and anyway, it's all clear from the pictures.)

So there you have it: a motorway that's also a wonderful day out. And, uniquely in France, free - for the moment. We had the viaduct to ourselves: not, I feel, an experience likely to be repeated in summers to come. Make the most of it while you can.

BIG BRIDGES

The Millau Viaduct is indeed a record-breaking achievement - but the experts at Guinness World Records are at pains to point out that it hasn't beaten every superlative. It is, indeed, the world's tallest bridge, being the distance between the lowest point of the land it passes over to the tallest point of the construction, in this case 343metres. Thus it supplants the previous holder of that record, the Akashi-Kaikyo bridge, right, between Honshu and Awaji islands in Japan. The towers of the Japanese bridge reach a mere 297metres. The French authorities will be disappointed, however, to learn that the Millau Viaduct is not in fact the highest bridge in the world - that is as measured form the lowest point of the territory it crosses to the actual roadway of the bridge, rather than its pylons and towers. On that definition, the title of highest bridge in the world still belongs to the bridge over the Royal Gorge of the Arkansas River in Colorado, USA. The Royal Gorge Bridge's roadway, below, stands 321m above the water level of the river. The bridge was built in six months and finished on December 6, 1929.

Simply in terms of altitude, the Millau construction is also some way short of the prefabricated Bailey bridge erected by an Indian Army team led by Lt. Col. S.G. Vombatkere in August 1982 near Khardung-La, in Ladakh, India. This is a breathtaking 5,502 metres above sea level but only 30 metres across.