The Strait of Gibraltar between Europe and Africa isn’t the only waterway that connects the Atlantic Ocean to the Mediterranean Sea. A thousand kilometer north lies another connecting route. This route connects the French city of Bordeaux, near the Atlantic ocean, to the Mediterranean port of Sète through a series of canals collectively called Canal des Deux Mers, or the “canal of the two seas.” Lying entirely in Southern France this man-made canal is one of the most remarkable feats of civil engineering carried out in the 17th century.
Canal des Deux Mers consist of two canals. From the Mediterranean port of Sète to Toulouse, a distance of 240 km, runs Canal du Midi. From Toulouse to the town of Castets-en-Dorthe, 193 km away, the canal is called Canal de Garonne. The remainder of the route to Bordeaux uses the Garonne River. The two canals—Canal du Midi and Canal de Garonne— together with the Garonne River form the Canal des Deux Mers which connects the Mediterranean Sea to the Atlantic Ocean. Often, the entire canal is called Canal du Midi.
Before the canal was constructed, the month-long sea voyage through the Straits of Gibraltar was fraught with dangers, mostly from pirates and intense storms the strait was subjected to because of its shape and physical geography.
The possibility of building an alternative route through France was first discussed by the ancient Romans. Later, many French kings expressed interest in constructing a canal which could avoid the passage around Spain, but the technological challenges were too great to overcome. The primary difficulty was in supplying sufficient water at the watershed, which is at a much higher elevation between the Mediterranean and the Atlantic.