Incredibly, it wasn’t until I was 19 that I learned that there had been a Holocaust. My hyper-assimilated, New England Jewish family and friends looked only to the present and future. We focused on the polio vaccine that promised to banish the iron lungs that had been our childhood terror. We trusted in the United Nations, whose gleaming buildings my father took me to see when they were brand-new, and from which I came away with hopeful admiration—mixed, however, with a vague sense, which I couldn’t have put into words then, that perhaps an enterprise housed in architecture so grandiosely...