Outside, at the end of a short corridor, we climbed an enclosed flight of concrete fire stairs to a door that opened onto the roof. The morning rain had stopped, the sky was nearly clear again except for horizon clouds, and several girls and men were sitting out there in canvas chairs, their faces lifted to the sun. At the sound of our feet on the gravel as we stepped out onto the roof, they turned and spoke, and Danziger smiled and flicked his hand in a wave. The rooftop was immense; a city block square of tar and gravel, ordinary enough except for scores of new skylights set into it, and a forest of stacks and vents. Ducking under rusting guy wires attached to the taller stacks, walking around an occasional puddle, we crossed to a glob of noon shade around the base of the wooden water tower. Danziger cut into his pie, and I stood looking around.

Far to the south and east, I could see the outsize bulk of the Pan Am Building overshadowing and dwarfing the entire area around Grand Central Station. Beyond it I saw the dull-gray tip of the Chrysler Building, and to the right of that and farther south the Empire State Building. After that, there was only a nearly solid wall of mist already stained yellow with industrial smoke. To the west, only a block or so away, lay the Hudson River looking like the opaque gray sewer that it is. On its other shore rose the cliffs of New Jersey. To the east I saw a between-buildings sliver of Central Park.

Danziger gestured at the invisible horizons with his fork and said, "There lies what? New York? And the world beyond it? Yes, you can say that, of course; the New York and world of the moment. But you can equally well say that there lies November twenty-sixth. Out there lies the day you walked through this morning; it is filled with the inescapable facts that make it today. It will be almost identical tomorrow, very likely, but not quite. In some households things will have worn out, used today for the last time. An old dish will have finally broken, a hair or two come out gray at the roots, the first flick of a new illness begun. Some people alive today will be dead. Some scattered buildings will be a little closer to completion. Or destruction. And what will lie out there then, equally inescapably, will be a little different New York and world and therefore a little different day." Danziger began walking forward toward an edge of the roof, cutting off a bite of pie as he walked. "Pretty good pie. You should have had some. I made certain we got a damn good cook."

It was nice up here: As we walked, the sun, deflected up from the rooftop, felt good on the face. We stopped at the edge of the roof and leaned on the waist-high extension of the building wall, and again Danziger gestured at the city. "The degree of change each day is usually too slight to perceive much difference. Yet those tiny daily changes have brought us from a time when what you'd have seen down there instead of traffic lights and hooting fire engines, was farmland, treetops, and streams; cows at pasture, men in tricornered hats; and British sailing ships anchored in a clear-running, tree-shaded East River. It was out there once, Si. Can you see it?"

I tried. I stared out at the uncountable thousands of windows in the sooty sides of hundreds of buildings, and down at the streets nearly solid with car tops. I tried to turn it back into a rural scene, imagining a man down there with buckles on his shoes and wearing a pigtailed white wig, walking along a dusty country road called the broad way. It was impossible.

"Can't do it, can you? Of course not. You can see yesterday; most of it is still left. And there's plenty of 1965, '62, '58. There's even a good deal left of nineteen hundred. And in spite of all the indistinguishable glass boxes and of monstrosities like the Pan Am Building and other crimes against nature and the people" — he waggled a hand before his face as though erasing them from sight — "there are fragments of still earlier days. Single buildings. Sometimes several together. And once you get away from midtown, there are entire city blocks that have been where they still stand for fifty, seventy, even eighty and ninety years. There are scattered places a century or more old, and a very few which actually knew the presence of Washington." Rube was up here now, I saw, wearing a felt hat and a light topcoat, deferentially waiting a few token paces out of earshot. "Those places are fragments still remaining, Si" — Danziger's fork swept the horizon once more — "of days which once lay out there as real as the day lying out there now: still-surviving fragments of a clear April morning of 1871, a gray winter afternoon of 1840, a rainy dawn of 1793." He glanced at Rube from the corner of his eye, then looked back to me. "One of those survivals, in my opinion, is close to being a kind of miracle. Have you ever seen the Dakota?"

"The what?"

He nodded. "If you'd ever seen it, you'd remember that name. Rube!" Rube stepped smartly forward, the alert lieutenant responding to the colonel's call. "Show Si the Dakota, will you, please?"

Outside the big warehouse, Rube and I walked east to Central Park; I'd picked up my hat and coat in the little ground-level office. In the park we turned onto West Drive, which is the street just inside the western boundary of the park. We walked along under the trees; a few still had their leaves, clean and greener now after the morning's rain, and Rube said, looking around us, "This park itself is something of a miracle of survival, too. Right here in the heart of what must be the world's most changeable city are, not just acres, but several square miles that have been preserved practically unchanged for decades. Lay a Central Park map of the early eighteen eighties beside a map of today, and there on both maps are all the old names and places: the reservoir, the lake, North Meadow, the Green, the pool, Harlem Mere, the obelisk. We've photocopied some of the old maps to precisely the size of a modern one, then superimposed one over the other between glass sheets, and shot a good strong light through them. Allowing for small mapmakers' errors, they've coincided, the sizes and shapes of the things in the park unchanged through the years. Si, the very curve of this road, and nearly all the roads and even the footpaths, are unaltered."

I didn't doubt it; off to our left, the low boundary wall of the park was not quick-poured concrete but old carefully mortised cut-stone, and the very look of the park, of its bridges and even its trees, is old. "Details are changed, of course," Rube was saying. "The kinds of benches, trash baskets, and painted signs, the way the paths and roads are surfaced. But the old photographs all show that except for automobiles on the roadways there is no difference you can see from, say, six or seven stories up." Rube must have timed what he was saying, or maybe it was past experience at this, because now as we passed under a final tree beside the walk, rounding the curve that led off the West Drive and onto the Seventy-second Street exit from the park, he lifted an arm to point ahead. As we walked out from under the branches of the tree he said, "From an upper apartment of that building, for example," and then I saw it and stopped dead in my tracks.

There across the street just outside the park stood a tall block-wide structure utterly unlike any I'd ever before seen in all New York. One look and you knew it was what Danziger had said: a magnificent survival of another time. I later came back — it was after a snowfall, as you can see — and took photographs of the building, a whole roll of them, the super even taking me up to the roof. The one at the top of the next page I took from where Rube and I stood; the building you see there is pale yellow brick handsomely trimmed in chocolate-colored stone, and as one of my later shots shows, each of its eight stories is just twice as high as the stories of the modern apartment house beside it.