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
Millau Viaduct World Wildlife Fund (WWF), "France Nature Environnement", the national federation of motorway users, and Environmental Action. Opponents advanced several arguments: Two weeks after the laying of the first stone on December 14, 2001, the workers started digging the deep shafts. There were four shafts per pylon; deep and in diameter, assuring the stability of the pylons. At the bottom of each pylon, a tread of in thickness was installed to reinforce the effect of the deep shafts. The of concrete necessary for the treads was poured at the same time. In March 2002, the pylons emerged from the ground. The