ecluse saint-pierre lock at canal de brienne, toulouse, connecting the garonne river with the canal du midi & the canal de garonne

south france midi languedoc canal brienne toulouse french engineering pont jumeaux lock ecluse join atlantic mediterranean construction work greatest world garonne river deux mers terminal pyrenees center town europe architecture outdoor detail saint-pierre connecting long southern forms des joining considered one century tourism tourist attraction travel france europe european saint pierre south languedoc occitanie water waterway popular