(Reuters) - A wine plague spread by lice destroyed vines in France in the 19th century but a small area in the Pyrenees, which contains plants up to 200 years old, was spared and is being classified as a national heritage monument. Like other national treasures such as the Palace of Versailles and Notre Dame cathedral, the vines in the Ardour valley will be protected. They contain the ancient DNA of local grape varieties. Some grapes are still being used with grapes from younger generation vines to make Saint-Mont wine.