Tarn (river) a mean flow of approximately . The Millau Viaduct spans the valley of the Tarn near Millau, and is now one of the area's most popular attractions. The tributaries of the Tarn include: The Tarn separates the Narbonne and Aquitaine basins. The Tarn passes through the following departments and towns: The Millau Viaduct, the tallest bridge in the world, carrying the A75 autoroute across the Tarn Gorge near Millau, opened in December 2004. The Tarn is famous for its brutal floodings, which are the most dangerous in Europe along with the Danube. The flooding of March 1930 saw the Tarn
Massif Central called "causses" in French, consists of raised chalky plateaus cut by very deep canyons. The most famous of these is the Gorges du Tarn (canyon of the Tarn). Mountain ranges, with notable individual mountains, are (roughly north to south): The following departments are generally considered as part of the Massif Central: Allier, Ardèche, Aude, Aveyron, Cantal, Corrèze, Creuse, Gard, Haute-Loire, Haute-Vienne, Hérault, Loire, Lot, Lozère, Puy-de-Dôme, Rhône, and Tarn; these form parts of the regions of Auvergne-Rhône-Alpes, Nouvelle-Aquitaine and Occitanie. The largest cities in the region are Clermont-Ferrand, Limoges, and Saint-Étienne. Massif Central The Massif Central (; ) is a