Does memory have a colour? If it does, it must lie somewhere between sepia and mahogany. A beautiful word that latter, even if I hear it as the spaced-out syllables of Brecht's decadent city, Mahagonny. Maha-gon-ny. In any case redolent of stiffbacked Victorian furniture, daguerreotypes, havanas, Worcestershire sauce, cocoa and the meat extract Nietzsche used to be partial to. The thick brown gravy of memory, Europe's edible mud.

And the more I look around, the more I seem to notice unstated official recognition of my observation. Memory is brown. Drive down the super-efficient tollways after the Channel Tunnel, those long concrete snakes cut around the contoured hills and ideological carcases of la bonne vieille France, and you can hardly miss them, warm ochre panels pointing out one architectural marvel after another, one battlefield after the next, great ark-like cathedrals bearing a generation's collective undertakings and understanding into the next. Cut off from the landscape by the metal cocoon of your car the brown signs come and go: pointers to what you might have slid through, at high speed, unawares. Little didactic lessons for the day, lozenge-sized verbal incarnations of the old continent. And by the time you turn east of Paris to travel the four hundred odd kilometres to the flatland of the Rhine Valley - Verdun, le grès rose de Vosges, Strasbourg et sa cathédrale - and Germany takes over, you've realised it at last: Europe is one enormous museum. Perhaps you'll stop in Strasbourg to ...