Carcassonne's old city—simply and universally called La Cité—is said to be one of the most magnificent sights in France, and I believe it. As unlikely as a battleship in a cornfield, its cone-roofed towers and miles of walls, ramparts and crenellations look like part of a life-size Dungeons & Dragons game. Whether the tower roofs are too pointed or should be wood-shingled rather than slate, whether there are too many crenellations or there's too warlike a basilica bell tower (which experts and dilettantes argue about to this day), it's no Disneyland.

At dinner, the French couple at the next table are openly contemptuous of us, perhaps because we're American or perhaps because we're having too much fun. But the woman loses her license to condescend when she heavily waters her wine.

Day 4: Carcassonne to St-Pierre-des-Champs
This is the first time I've driven such a conspicuous consumer as the Quattroporte with caution and reserve rather than my usual excess and abandon. Our tank holds 23.8 gallons, the Maserati gets about 15 miles per, and a gallon of petrol is around $8. I find myself gentle on the throttle and venture nowhere near the car's enormous acceleration and top-speed capabilities.

We're accustomed to 24/7 gas at convenience stores, two or three competing at every major American intersection. Gas pumps in the south of France, however, are occasional, close for two-hour lunches, and aren't open at night. Or, as we discover, on Sundays. The sole unattended but automatic station we find won't accept any of our credit cards. Fortunately, we still have a quarter of a tank, aren't going far, and will spend more time happily wandering afoot than driving.

Oddly, the twelfth-century castle high above Termes wasn't even listed as a historic site until 1951—just a lot of useless rubble—and didn't officially become one until 1989; France has more history than it knows what to do with. (This was the sole Cathar castle to be both besieged and defended by catapults.) Louis XIV had ordered that the thing be torn down so that "no stone remain on a stone." A local mason spent almost a year single-handedly trying to do so. His tons of rock pile remain, though so do some of the walls and interior foundations.

Day 5: St-Pierre-des-Champs to Tautavel
Nearly two million years ago, humankind evolved in Europe, some of it eventually finding its way to the shelter of the caves and grottoes that formed in the limestone cliffs and outcrops of the Pyrenean plains and foothills. They were pre-Neanderthal—they made no use of fire—but did figure out how to make the most basic Stone Age cutting tools and may even have had a primitive form of language.

Once it crosses the coastal ridge and leaves the industrious bustle of the Perpignan suburbs behind, the small D-road from the A-9 autoroute to the European Prehistory Center at Tautavel enters a sere, boulder-strewn landscape that probably doesn't look much different than it did when Tautavel Man, a stray member of a group more formally known as Homo heidelbergensis, roamed it 450,000 years ago. There is no sign of civilization but the road itself, and the rugged, distant escarpments are where he (and of course she) lived, in the Cave of Arago, with a commanding view of the flatlands through which we're driving.