Rendering of 111 West 57th street as seen from Top of the Rock at Rockefeller Center.
Image: JDS Development Group

The lectures compiled here on the subject of New York's super-slender skyscrapers span several years, both before and during the Museum's 2013-14 exhibition SKY HIGH & the Logic of Luxury, first defined the emerging typology. Also compiled are several 20-minute papers delivered at conferences of the CTBUH from 2014-2016 by Carol Willis that present an overview of the subject. Because this page is for the most part a historical record of the research for SKY HIGH, including lectures presented by the architects, engineers, and developers of some of the towers then under construction, the charts and graphs have not been updated and remade. Indeed, it is significant that since 2016, there have been no new towers constructed that are as super-slender as this group.


  • 111 W. 57th St.: Vishaan Chakrabarti, Partner, SHoP Architects; Gregg Pasquarelli, Partner, SHoP Architects; Silvian Marcus, Principal in Charge, WSP Group; Carol Willis (moderator), Director of The Skyscraper Museum; Michael Stern, Managing Partner, JDS Development Group (March 11, 2014)
  • 432 Park Avenue: Rafael Viñoly (February 24, 2014)
  • CTBUH talks: Carol Willis (2014-2016)
  • 125 Greenwich Street: Jae In Choi, Rafael Viñoly Architects, and  Stephen DeSimone, DeSimone Consulting Engineers (April 24, 2018)
  • Super Slender Midtown Towers: Carol Willis (February 19, 2009)

Mirror, Mirror… Who is the Slenderest of them All?

March 11, 2014

Among the extraordinary new crop of New York’s super-slim, ultra-luxury residential towers surveyed in The Skyscraper Museum’s exhibition SKY HIGH & the logic of luxury, the most slender of all is the 111 W. 57th St., designed by SHoP Architects, with structural engineering by WSP Group for JDS Development Group and Property Markets Group. With a ratio of the width of the base to height of 1:23, the 1,350+ ft tower will be the most slender building in the world.

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SHoP’s design harkens back to the quality, materiality, and emphatic verticality of historic NYC skyscrapers, while utilizing advanced engineering and technology to craft a contemporary contribution to the skyline. The tower’s silhouette rises in an elegant series of feathered setbacks, while the facade reads at multiple scales and vantage points. An intricate pattern of shaped terracotta panels and bronze latticework on the east and west facades creates a sweeping play of light and shadow, while a glass curtain wall on the north and south facades provide sweeping views of Central Park and Midtown.

SHoP Architects was founded in 1996 on the premise of proving that intelligent and evocative architecture can be made in the real world, with real-world constraints, and has made a name for itself by pioneering the use of innovative technologies to produce both iconic architectural forms and a new model for the profession.

WSP is one of the world’s leading professional services firms. Its New York-based structural engineer, the WSP Group (formerly Cantor Seinuk) are the designers of the structural systems for a majority of the city’s super-slender towers now under construction.

At Edmond J. Safra Hall, Museum of Jewish Heritage 36 Battery Place, across the street from The Skyscraper Museum.


432 Park Avenue and Other Towers

February 24, 2014

Rafael Viñoly

Taller than the rooftop of either the original or current 1 WTC, 432 Park Avenue will top out in 2015 at 1,396 feet, making it–in the words of its developers Macklowe Properties and the CIM Group–the loftiest residence “in the Western Hemisphere.” Exemplifying “the logic of luxury,” the tower’s soaring height is predicated on its compact 93-foot square floor plate and extra-high ceilings, which produce its slenderness ratio of 1:15. The emphatic white grid of the concrete frame, divided into six sections by open mechanical floors, represents an integration of the elegant architectural concept and structural logic that sets 432 Park Avenue apart from curtain-wall contemporaries.

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Rafael Viñoly is the founding principal of Rafael Viñoly Architects PC, a New York-based firm with international practice. Viñoly’s award-winning designs include museums, performing arts centers, convention centers, and numerous research and academic buildings and complexes. His commercial high-rise work began in the 1980s, and he explored innovative forms and structural strategies in several projects, including the post-9/11 WTC competition, in which the collaborative design of the THINK team for a World Cultural Center was a finalist.



Carol Willis

These talks examine the recent proliferation of super-slim, ultra-luxury residential towers on the rise in Manhattan. These pencil-thin buildings-all 50 to 90+ stories-constitute a new type of skyscraper in a city where tall, slender structures have a long history.

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Sophisticated engineering and advances in material strengths have made these spindles possible, but it is the excited market for premium Manhattan real estate that is driving both heights and prices skyward, Reported sales seem almost inconceivable: some penthouses in the buildings featured here are in contract for $47 million to $95 million. The rarified geographies of where these projects take shape and the economics of high land costs, high-style design and construction, and stratospheric sales prices are deconstructed. The buildings featured include the super-slender towers of the “57th Street phenomenon”-432 Park Avenue, One57, and the feather-thin 111 West 57th scheme-as well as downtown’s 56 Leonard, the Four Seasons at 30 Park Place, and the planned Tower D in Hudson Yards.

Ultra-luxury is a distinct clientele, to which the towers’ developers direct their branding and marketing psychology. But there is also a “simple math” in the logic of luxury that shapes the design of these projects in every aspect.

Carol Willis is the founder and director of the Skyscraper Museum and a professor of Urban Studies at Columbia University’s Graduate School of Architecture, Preservation and Planning. She is also the author of Form Follows Finance and co-author of Building the Empire State with Donald Friedman.

125 Greenwich Street

April 24, 2018

Jae In Choi, AIA, NCARB, Project Manager, Rafael Vinoly Architects

Stephen DeSimone, AIA, NCARB, Project Manager, Rafael Vinoly Architects

The one constant in the evolution of the design of the 912-foot tall, super-slender condominium at 125 Greenwich Street, just south of the World Trade Center site in lower Manhattan, is its postage-stamp site, barely 83′ x 119 ft. After several early schemes, which ranged in height from 1,100 to nearly 1,400 ft., the tower now under construction will top out at 912 ft./ 278 meters. Offering insights into their strategies of design and structural engineering of the skyscraper are Jae In Choi, the project architect from Rafael Vinoly Architects, and structural engineer Stephen DeSimone of DeSimone Consulting Engineers.

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In the changing market for luxury units and the evolving Downtown demographics, the developer’s continuing analysis led to a rethinking of the mix of apartments and placement of amenity floors and, thus, a revised structural approach and expression in the tower’s form. Choi and DeSimone will detail how the current design answers the challenges of mixed floor plans, maximized views, and wind engineering, among other issues.

125 Greenwich Street is being developed by Bizzi & Partners, a global real estate firm with offices in Milan, New York, San Paolo and Tallinn. In addition to Rafael Vinoly Architects and DeSimone Consulting Engineers, consultants to the project include Reginald D. Hough Associates, Cosentini Associates, and Robert Schwartz & Associates.

Join the speakers for another program in the Museum’s continuing series of Skyscraper Seminars, exploring subjects of theory and practice for design professionals.

Jae In Choi, AIA, NCARB is a Project Manager at Rafael Vinoly Architects, where is managing 125 Greenwich Street. He has worked at RVA since 2010, where he has been the Project Manager for 432 Park Avenue, among other buildings.

Stephen DeSimone joined his father and the firm in 1988 and is now President and CEO. Focusing especially on residential projects, DeSimone’s recent designs in New York City include the super-slender towers 220 Central Park South, 125 Greenwich Street, 252 E. 57 Street, 50 West Street, and 45 E. 22 Street.

Super Slender Midtown Towers

February 19, 2009

“Hong Kong slender” describes a type of pencil-thin tower common in Asia’s Manhattan and recently returned to New York real estate. In conjunction with its current exhibition, “Vertical Cities: Hong Kong | New York”, The Skyscraper Museum examined the aesthetics, engineering, and economics of slenderness in a program highlighting three tall, super-slim residential towers recently reared in Midtown: Sky House, One Madison Park, and 785 Eighth Avenue. Team presentations by the architects, structural engineers, and developers explored the complex equation of twenty-first century slenderness.
Read more/less Sky House One Madison Park 785 Eigth Avenue