The fifty-nine-story Citicorp building, completed in 1977, is elevated by four monumental, squared columns. Photograph by François Roux / Alamy

If the Empire State Building and the Chrysler Building are the romantic leads in the drama of the Manhattan skyline, then the nearby Citicorp building, now formally known by its address of 601 Lexington Avenue, is the trusty best friend. There it is, with its distinctive forty-five-degree rooftop slope and its silvery aluminum cladding, right after Empire and Chrysler in only the third shot of the clarinet-croon opening of “Manhattan.” When Woody Allen made that film, the fifty-nine-story tower, completed in 1977 and designed by the architect Hugh Stubbins, Jr., was just over a year old, but was already an indispensable part of the skyline’s accidental beauty. Its tilted top was the architectural leftover of an abandoned idea for terraced penthouses, and perhaps for a solar-panel array—but mostly it was pure style, a new way of nodding to the old idea of a spire.

How the building met the ground was even more remarkable than how it met the sky. The northwest corner of the block, at East Fifty-fourth Street and Lexington, had been occupied, since the turn of the century, by St. Peter’s Lutheran Church, which agreed to Citibank’s project on the condition of space between the sacred and profane: that a new church be built and that the new tower would not touch it. Stubbins, and the structural engineer William J. LeMessurier, made the most of this constraint, lifting the skyscraper onto four monumental, squared columns, a hundred and twenty-seven feet in height. The columns were positioned not at the building’s corners but at the center of each side: cantilevering those corners seventy feet out in space, making the skyscraper appear to float, and opening up the northwest corner for the church. (In a story largely unreported until 1995, this audacious structure was quietly reinforced, in 1978, after it was determined that the engineers hadn’t factored in the potentially catastrophic loads of quartering winds.) The new St. Peter’s Church, by Stubbins and the architect Edward Larrabee Barnes, is as rocky as its name: a sculpturally chiselled outcrop of granite boldly distinct from the glass-and-aluminum tower, and evoking, without kitsch, everything pointy and heavy about a well-made church.

The finest part of the new urban composition was a sunken plaza, a dozen feet below sidewalk level. Entered from the block’s southwest corner and uncannily sheltered by the underbelly of the elevated skyscraper ten stories overhead, it was a consequence of the city’s “plaza bonus” zoning, which allowed developers to build higher in exchange for incorporating public space into their property. It was the work of Hideo Sasaki, one of a great generation of landscape architects—Dan Kiley, Lawrence Halprin and Harriet Pattison prominent among them—who worked alongside such familiar heroes of mid-century modern design as Eero Saarinen and Louis Kahn. The plaza’s main feature was a monumental sculptural fountain at the busy intersection of Lexington Avenue and East Fifty-third Street—a kind of miniature concrete mesa or butte with lively waterfalls running down its sides, extending up above the sidewalk and down to the plaza below, casting the sound of running water over the noise of the avenue.

The sculptural fountain served as a kind of urban newel post, turning the corner between broad steps that accommodated heavy foot traffic up to the plaza from a subway stop at the intersection of two major lines, and up again to the sidewalk. The stepped geometry of the fountain extended seamlessly into the steps themselves: seen from above, the steps were angled, starting out parallel to Fifty-third Street and facing a church entrance on the north side of the plaza, and then bending forty-five degrees to face a tower entrance. This angle was echoed further, like a ripple in water, in another shallow set of steps that extended across the whole plaza—as if the weight of the skyscraper’s monumental column had gently pressed the plaza deeper into the earth. Above that ripple of steps was a grove of trees; below it, sheltered a further five feet below the bustling sidewalk with a dozen tables and chairs, was an oasis in which to peacefully people-watch the commuters hustling from subway to sidewalk. The effect of the bend in the entrance steps, and its echoing ripple across the plaza, was to make approaching from the intersection less like taking another staircase in a city full of them, and more like gently descending the side of a giant boulder, like those in nearby Central Park—a piece of architectural geology. The whole was originally surfaced in warmly earth-toned, brick-like pavers that extended all the way from the plaza up across the adjacent city sidewalks, amplifying the sense of place and of lively exchange between public and private, civic and sacred, hectic and calm.

This summer, it was bulldozed. New York City’s Landmarks Preservation Commission declared the Citicorp complex a protected landmark on December 6, 2016, but between that designation and its earlier “calendaring” (the scheduling of a public hearing and the first formal step in the designation process) in May of last year, approvals for demolition and new construction were secured. The landmark designation report concedes that, “Prior to designation and after City Planning Commission review and approval, the owner of Citicorp Center obtained Department of Buildings’ permits to modify the sunken plaza,” but promises, “the Landmarks Preservation Commission will review future proposed alterations to these public spaces.”

In the plaza of the Citicorp Center, sheltered well below the bustling sidewalk, was an oasis in which to peacefully people-watch the passing commuters. Photograph by Sergi Reboredo / Alamy

Those future proposed alterations would be not to the historic plaza but to its replacement, now under construction—part of a comprehensive renovation of the lower levels and internal atrium of the Citicorp complex, intended to make it a more enticing place to shop and eat lunch. It’s the work of Gensler, a global design firm specializing in everything from airport terminals to corporate offices. “While the original design of the public plaza and atrium was striking, the spaces were not inviting to the public and lacked connectivity,” the Gensler principal Joseph Lauro said to the design journal ArchDaily in March. “We believe our design will bring vibrancy to the Midtown East neighborhood by seamlessly integrating these public amenities while respecting the iconic architecture.”

Based on the renderings that now adorn the plywood construction barriers around the site, one can make the case for the new design: it’s simpler to navigate because, minus Sasaki’s ripple of stairs across the plaza’s broadest expanse, it’s shallower and flatter; it’s warmer, because the new benches are made of wood; it’s greener, because there will still be trees, plus some new flower beds, with what look like lilacs; it’s smoother and safer to commute through, because the two major flights of steps, from the sidewalk at the corner of Fifty-third and Lexington down to the plaza, and from the plaza down to the subway, have been widened and straightened; it’s funner, because there’s a retro-industrial, casement-style window that flips up to make an awning over a hole-in-the-wall emporium under the Lexington Avenue sidewalk, plus an eminently Instagrammable paving pattern scintillating across the ground. Symmetrically paired with a narrow slope of ivy on the opposite side of the new corner staircase is a modest water feature in the approximate location of the lower part of Sasaki’s sculptural fountain: what appears to be a tidy triangle of tilted panels, with a shallow film of water sliding iridescently down them.