The Garonne is one of the largest rivers in France. It has its source near the Spanish border, and it flows 521.9 km across the country. It reaches the Atlantic Ocean at Bec d'Ambes, just outside Bordeaux. This is where it joins the Dorgogne to form the Dordogne estuary. Throughout history, the Garonne has been a navigable river, although it can be unpredictable. It is also used for hydro-electricity, and by the nuclear industry.