There is a moment on the approach to Château de la Treyne that stays with you forever. As you drive across a narrow suspension bridge spanning the Dordogne River, you look up to see a dramatic 14th-century fortress perched high on a limestone cliff. Its beautifully proportioned towers and weathered stone battlements cast perfect reflections on the water below. Even after 40 years of travel writing, I found myself turning to my wife, Sue, and uttering: "Blimey! Are we really s