The back story of al-Qaida’s latest New York target.

Sound structure?

Can a skyscraper be cursed?

That’s the question that nervous Citigroup executives must be asking themselves this week after learning that their skyscraper in Midtown Manhattan has apparently been scouted by al-Qaida operatives as a possible target. After all, it was 26 years ago that the same building was the source of nearly a summer’s worth of sleepless nights for officials at the company, then called Citicorp, after they found out that it was in danger of collapsing in a storm with high winds. At that point in New York’s history, of course, the catastrophic effects of a skyscraper crashing to the ground could only be imagined, and the crisis produced a few jokes about the building falling onto Bloomingdale’s.

The silver-colored 59-story tower, with its diagonally sloping top, was designed by the architect Hugh Stubbins in the mid-1970s. From the beginning, the Citicorp tower was unusual, if not exactly radical, structurally. Its site, at 53rd Street and Lexington Avenue, originally included an old church, St. Peter’s; when Citicorp bought the plot it offered to rebuild the church in the same location, and to design the tower around it. To give the new church some breathing room, Stubbins and the structural engineers on the project hoisted their tower into the air above it. They connected the tower to the ground with nine-story-high columns, which are covered like the rest of the building in shimmery aluminum panels. (The columns are placed in the middle of each side of the building instead of at the corners.) The result is a skyscraper that looks like it’s raised on stilts, hovering dramatically above the new St. Peter’s and the pavement.

When the tower opened in 1977 as Citicorp Center, nobody had any reason to worry that Stubbins’ solution had produced anything but a reliable piece of commercial architecture. But the following year an unusual sequence of events unfolded. First, the main structural engineer on the project, William J. LeMessurier (pronounced “Le Measure”), discovered that during construction some of the connections in the tower’s wind braces had been bolted instead of welded. (Welding joints makes them stronger, but it also costs a lot more than bolting.) Then an engineering student in New Jersey whose professor had criticized the placement of the columns on the building called LeMessurier to ask a few questions for a research paper. The call prompted LeMessurier to go back and reassess his work on the tower.

Bright, shining … target?

After a long and involved series of calculations, he discovered, with dread, that the bolting and some other structural anomalies had combined to leave the building shockingly vulnerable to high winds hitting it at a 45-degree angle–vulnerable enough that a so-called 16-year storm (one, in other words, that could roughly be expected to arrive once every 16 years) might be enough to topple it. He took the news to Citicorp execs, who set about repairing the building as quickly as possible, with workers tearing apart office walls to reach the steel frame and welding the connections at night. As hurricane season neared, the company sent out press releases manufacturing benign reasons for the new construction, and a newspaper strike helped keep the real story out of print.

At least for a while. If these events sound familiar, it’s because they were the subject of a long article in The New Yorker in 1995 by Joe Morgenstern—probably the only suspenseful magazine story ever written about structural engineering. Morgenstern, now the film critic for the Wall Street Journal, reportedly heard the cliffhanger about the skyscraper at a dinner party many years after the fact. His piece about the incident, “The Fifty-Nine-Story Crisis,” painted LeMessurier as a kind of hero, the protagonist of a story about a professional and moral test. The story, Morgenstern wrote in the concluding paragraph, “speaks to the larger question of how professional people should behave.” The article was for a while on everybody’s lips. Paramount bought the movie rights.

If the recent news reports are to be believed, it was soon after the piece was published that al-Qaida began casing the building. Might its unusual history have made it more attractive to the terrorists as a target? It’s tough to say.

On one hand, it does seem possible that al-Qaida picked the building because, in addition to its self-evident symbolic value, its gigantic exposed columns at street level make it appear highly vulnerable to a car or truck bomb. It’s well known and hardly surprising that al-Qaida pays careful attention to the precise weaknesses of its architectural targets, from the American embassies in Africa that were bombed in 1998 to the World Trade Center towers themselves. On the other hand, you could also argue that the drastic fortification of the building’s structure—if only against the wind—might have already been enough to give would-be attackers pause. If that’s the case, then LeMessurier’s willingness to own up and fix the tower’s problems may have prevented more than just a meteorological disaster.