Leaning back on my bench, I marveled at the floodlit facade of Chartres Cathedral. Munching on my baguette with brie, I was pondering how, for centuries, nobles and peasants alike have been awestruck by this view. Then in my periphery, I noticed a bum on the next bench, reaching toward me — and offering me a swig of red wine from his battered 1.5-liter plastic water bottle. Backlit by the floodlighting and with a twinkle in his friendly eyes, he looked like a character in an over-the-top rom...