The site is as tidy and anonymous now as a hospital room after the patient has left, or died. The slabs of pale concrete look like the beginning of something, not its end, as though at any moment workers, whistling, carrying lunch, will begin to raise the girders and frame the walls as workers have done in New York City for as long as anyone can remember. It does not look like a mass grave. It does not look like a crime scene. It does not look like a historical site. It is all of those. It looks like a...