They call it an incredible feat of civil engineering. They say it is one of the longest canal systems in the world, the most spectacular man-made waterway. They inscribe it with World Heritage status. But the Canal du Midi is a living work of art that slowly coils through the French countryside from the Mediterranean clear across the country to the Atlantic – a full three hundred and sixty thousand kilometres – passing under ancient Roman aqueducts, through tunnels and locks, lined by majestic plane trees (may the fungus attacking them die abruptly with these words). Barges pass slowly along, leaves stir in the summer wind, a chorus of frogs croak lazily as night approaches. One day I will travel its full length on a sleepy barge from Vias in the east to Bordeaux in the west, very very slowly…