The Rhône is over 800 kilometres long and is one of the most important wine rivers in the world. Like all watercourses, it has a positive effect on viticulture and creates the conditions for this by forming valley slopes, some of which are very steep. The river has its source at the Furka Pass as a glacial stream in the Swiss Alps of Uri, flows through the canton of Valais and Lake Geneva under the name Rotten, crosses the French border, turns south from Lyon and flows into the Mediterranean Sea south of Arles-sur-Rhône. The Greeks founded in the 6th century b. C. The Greeks founded the city of Marseille (Massilia), situated at the mouth of the Rhone, and brought the vine into the valley. Also the Celts (Gauls) already practiced viticulture in today's appellations Côte Rôtie and Hermitage (Crozes-Hermitage). Allegedly they taught the Romans the art of grafting.