It reached its mid-point 80 years ago this weekend, and is embedded in the French psyche as the ultimate reason why today's entente with Germany, and the existence of the European Union are not only desirable, but so utterly essential.
Verdun, fought through the ice and snow of winter, the damp and rain of spring and autumn and the blazing heat of summer, at a cost of almost 400,000 young French lives, is a word that has only to be mentioned to elicit the immediate response: "Never again."
It conjures up for French people the same images of hell - the mud and damp of the trenches, the rotting boots and lice, the unburied bodies, the moaning of the injured who could not be rescued - that are so familiar to Britons from the letters and poems of the period.
But for the French there is one difference: not only were the soldiers and the questionably competent generals theirs, but also the land, land that is now strangely hilly and green, with mounds and bushes and trees that look too new and young for the landscape. You can scarcely drive a mile without finding the entrance to a bunker or fort, the remnants of a trench, or a ruined village, where only a few stones remain to tell of what was once there.
The town of Verdun itself nestles in a bend of the river Meuse, surrounded by the undulating countryside of the Ardennes, a classic border town clustered around a massive, part-hidden fortress, and topped with a double- towered cathedral. At first sight, it looks like any other flourishing town in northern France: a bustling high street, an abundance of small shops and cafes, and a liberal scattering of north European and American touristsconsulting their maps.
Even in the bright light of early summer, there is a grimness and stoicism that betrays its battle-scarred past. There are narrow streets where the sun scarcely penetrates. The stone is cold and oppressive. A UN and Europe- sponsored world centre for peace in the former episcopal palace is deserted.
In the lower town, a bulky victory monument is wedged between the little houses of the high street. The tourists are there to see the battlefields and the memorabilia of war. War dominates Verdun still. For the 80th anniversary it has opened up its massive citadel, taking visitors eight at a time in little carriages through some of the chambers and passages where a dwindling number of defenders held out, despite lack of food, water and ammunition, until their surrender.
Reconstructions of the underground bakery and mess (stacks of baguettes; wine bottles and napkins on every table) show a French sense of priorities that endures. But the final tableaux, which present death and glory and patriotism as sombrely relevant for the France of today, drive home the message that Verdun for France is more than a battle. One of the last tableaux reproduces the ceremony at which, in 1922, a French soldier was detailed to choose from seven unidentified coffins draped in the tricolour which one was to be buried beneath the Arc de Triomphe in Paris, as France's unknown soldier.
Tomorrow, President Jacques Chirac and other French dignitaries will be in Verdun for a series of ceremonies centred on the French national cemetery and ossuary at the Fort de Douaumont where the names of French soldiers and the villages, towns they came from, are inscribed on every brick. Below, stretch line after line of white gravestones across the hillside and beyond, the endless landscape that soldiers still describe as "ideal battle country".
Inevitably, comparisons will be made with the last historic meeting at Verdun, in 1984, when Mr Chirac's predecessor, Francois Mitterrand, walked hand in hand with Chancellor Helmut Kohl of Germany among the graves of that same cemetery in a gesture of reconciliation that made headlines around the world. Mr Chirac has chosen a different symbol. Tomorrow, he will address an audience of 3,000 French and German teenagers with his own message of reconciliation: a message addressed to the future of the two old enemies, not to their past.