No mountains today. The structure comes from water, plane trees, towpaths and fields. From Toulouse, the route enters the Lauragais, with the Canal du Midi repeatedly pulling the eye back to the same line. At Naurouze, the watershed splits Atlantic and Mediterranean waters; after that comes Castelnaudary, all basin, locks and cassoulet reputation. The final kilometres into Carcassonne still ripple enough to keep the legs honest. Then the Cité appears: walls, towers and a drawbridge silhouette above the Aude.
