New York is full of giants. You walk down Lexington Avenue and you barely look up anymore because everything is a glass-and-steel behemoth competing for a slice of the clouds. But then there’s the Citi building New York—officially Citigroup Center, or 601 Lexington—and it’s just different. It’s got that 45-degree angled roof that looks like a solar panel from the future. It’s also sitting on "stilts" that are nine stories high. Honestly, it looks like a design choice made purely for the aesthetic, but the story behind why it exists is one of the most terrifying, high-stakes engineering blunders in human history.
If you’ve ever sat in the sunken plaza or visited the Saint Peter’s Church at the base, you’ve basically stood right in the middle of a miracle.
The Architectural Nightmare of 601 Lexington
When Citicorp decided to build a new headquarters in the early 70s, they hit a massive snag. A church. Saint Peter’s Evangelical Lutheran Church owned the corner of the lot. They weren’t moving. They let Citi build there, but only if the new skyscraper didn't touch the new church building. Most architects would have walked away. Hugh Stubbins didn’t.
He and structural engineer William LeMessurier came up with a wild plan: put the building on four massive columns. But here is the kicker—the columns aren't at the corners. They are in the middle of each side. This left the corners hanging out in space, cantilevered 72 feet. It looks cool. It was also, as it turns out, a ticking time bomb.
The Secret 1978 Crisis
In 1978, a student at Princeton named Diane Hartley started crunching the numbers on the Citi building New York for her thesis. She realized something LeMessurier hadn't fully accounted for: quartering winds. Usually, engineers calculate for wind hitting a building head-on. Hartley found that when wind hit the building diagonally, the stress on those weirdly placed stilts skyrocketed.
📖 Related: GA 30084 from Georgia Ports Authority: The Truth Behind the Zip Code
LeMessurier checked the math. He realized she was right. Then he found something even worse. During construction, the joints were supposed to be welded. To save money, the contractors used bolts instead.
One bad storm.
That’s all it would have taken. A 16-year storm—the kind of wind that happens in NYC fairly often—would have literally snapped the bolts, and the 59-story tower would have toppled onto midtown Manhattan.
What followed was a secret "fix-it" job that sounds like a spy movie. They didn't tell the public. They didn't even tell the NYPD at first. Every night for months, welders went into the building after the office workers left. They welded two-inch-thick steel plates over every single bolted joint. They did this while Hurricane Ella was brewing off the coast. The Red Cross and FEMA were secretly on standby to evacuate a 10-block radius if the wind got too high.
Why the Slanted Roof?
Everyone asks about the roof. Is it a solar collector? Nope. It was supposed to be. The original plan was to fill that 45-degree slope with solar panels to power the building. In the 70s, though, the technology just wasn't there yet. It wasn't efficient enough. So, they kept the slant because it looked iconic, but it’s basically just a very expensive, very steep mechanical penthouse now.
👉 See also: Jerry Jones 19.2 Billion Net Worth: Why Everyone is Getting the Math Wrong
Living With the "Tuned Mass Damper"
The Citi building New York was actually the first skyscraper in the U.S. to use a tuned mass damper (TMD). Imagine a 400-ton block of concrete sitting on oil bearings near the top of the building. When the wind blows the building to the right, a computer-controlled system pushes the block to the left.
It keeps the building from swaying so much that people get seasick. Without that TMD working during the 1978 crisis, the building’s chances of survival were basically zero. Even today, that block is up there, silently shifting back and forth to keep the office workers in their cubicles from feeling the 900-foot tower move.
Real Estate and the Modern Face of Citi
Citigroup doesn't even own the whole thing anymore. They sold the building to Boston Properties years ago but kept a massive presence there. In the last decade, the building underwent a massive $150 million renovation. They didn't touch the slant (obviously), but they completely redid the "Marketplace" at the base.
The plaza is now a massive glass atrium. It’s light, it’s airy, and it’s a far cry from the dark, concrete-heavy vibe of the 70s. You’ll find people eating $18 salads there now, completely unaware that the floor beneath them was once the site of a potential architectural catastrophe.
✨ Don't miss: Missouri Paycheck Tax Calculator: What Most People Get Wrong
- The Church: Saint Peter's is still there. It’s tucked under the stilts. It's a striking piece of architecture in its own right, often hosting jazz vespers.
- The Subway: One of the busiest hubs in the city (Lexington Av/53 St) sits right underneath. The engineering required to balance a 25,000-ton building on stilts over a subway vault is mind-boggling.
- The Height: It stands 915 feet tall. At the time it was finished, it was the seventh-tallest building in the world.
Why It Matters Today
The Citi building New York isn't just an office tower. It represents a specific era of New York ambition where we thought we could outsmart physics. It also serves as a massive lesson in ethics. William LeMessurier almost ruined his career by admitting the mistake, but he saved thousands of lives.
Today, the building is a designated New York City Landmark. You can't change the silhouette. You can't get rid of the stilts. It’s a permanent part of the skyline, a silver-and-glass reminder that sometimes the most beautiful things are the ones that were the hardest to keep standing.
Actionable Insights for Visiting or Researching
If you’re heading to Midtown to check it out, don't just look at the roof. Walk into the plaza at 53rd and Lexington. Look at the columns. Notice how they are centered on the faces of the building, not the corners. It defies your brain’s expectation of how a heavy object should stay up.
- Visit the Atrium: The public space is one of the best "Privately Owned Public Spaces" (POPS) in the city. It’s great for remote work if you can snag a table.
- Check the Jazz Schedule: Saint Peter's Church (the one that forced the building to be on stilts) has incredible acoustics. Their "Jazz Vespers" on Sundays are a local legend.
- Photography Tip: The best view of the slanted roof isn't from the base. Go a few blocks north or view it from the Roosevelt Island Tram to really see the angle against the rest of the skyline.
- Study the Case: For engineering or ethics students, the LeMessurier "Fifty-Nine-Story Crisis" is a foundational case study. Look up the original New Yorker article from 1995 by Joe Morgenstern—it’s the piece that finally broke the secret to the world.
The Citi building New York remains a triumph of both design and the "fix-it-at-all-costs" New York spirit. It’s a building that shouldn't work, but through a mix of secret midnight welding and a very heavy block of concrete, it’s not going anywhere.