France's longest river, the Loire begins in the Cevennes range of southern France, flows north to the center of the country, then flows due west to the Bay of Biscay. Many notable cities are on the river, including Nevers, Orleans, Blois, Tours, and Nantes. The Loire is sometimes called the 'last wild river in Western Europe,' and many proposed dams on the river have not been built because of opposition to the flooding of land and to interference with Atlantic salmon. The Loire Valley is particularly known for its vineyards and for its châteaux, a collection of over 300 castles dating to the 16th and 17th centuries.