The Canal du Midi, designed and built by the genius Pierre Paul Riquet, started in 1667 and opened for navigation in 1681.
From Toulouse to the étang de Thau, the 240 km long Canal du midi runs on double slopes regardless of the 189 metres high Seuil de Naurouze. There, it marks the division of the waters, which flow in one direction to the Atlantic and in the other to the Mediterranean. The locks allows the downstream or upstream passage of the boats.