River, southeastern France.
The longest river in France, it flows north and west for 634 mi (1,020 km) to the Bay of Biscay , which it enters through a wide estuary below Saint-Nazaire. Embankments were built as early as the 12th century, and in subsequent centuries it was used extensively for the transport of goods. A canal system built in the 17th and 18th centuries is inadequate for modern vessels.