Among the Loire’s charms is its wine. A tour of the valley’s 31 AOCs runs from Sancerre, esteemed for Sauvignon Blanc, westward through Chinon with its excellent Cabernet Franc, and into Vouvray for transcendent Chenin Blanc before hitting Muscadet near the coast. The 800-kilometer wine route is France’s longest and, arguably, most diverse. But with its slate, schist and limestone soils, and the river’s moderating influence on its climate, all of the Loire has terroir on its side. It also has history.