The Loire – France's longest river – covers so much. It runs from central France, alongside oak forests that supply the barrel industry, past the great Sauvignon Blanc regions of Sancerre and Pouilly-Fumé, and on to flow west, through the Chenin Blanc and Cabernet Franc heartlands of Anjou, Vouvray and Saumur before reaching the Atlantic near Nantes and the wine region of Muscadet.