I left Paris mildly haunted. Not by the piles of bones in those underground warrens, but by the comprehensiveness of our folly. What looked like human progress—all that milling, mass distribution, and preservation of food—had horrible consequences. Breathing slow, less, and exhaling deeply, I realized, none of it would really matter unless we were able to get those breaths through our noses, down our throats, and into the lungs.
