Rockefeller Center

Rockefeller Center, originally known as Radio City is a complex of buildings developed in the midst of the Great Depression. Initially the complex consisted of 14 buildings, the 70 story RCA building being the tallest. 


Metropolitan Opera

The area where the Rockefeller Center is located was originally planned as the new location for the Metropolitan Opera. At the time the area, situated between 48th and 51st streets and Fifth and Sixth avenues was a red-light district owned by Columbia University.

John D. Rockefeller Jr. leased the area on behalf of the Metropolitan Opera, also referred to as 'the Met'.

The design of the complex was created by the American architect Benjamin Wistar Morris. His plan, influenced by the Grand Central Terminal Complex included a landscaped garden and a monumental Opera House as well as tall office towers, shops and terraces. The buildings would be connected by an series of bridges and walkways.

However, the stock market crash of 1929 caused the Met to abandone the ambitious project. Rockefeller then launched a plan for a corporate complex to house the new radio and television corporations. Radio City was born.






























Radio City

One of the first buildings completed was the RCA building, which served as the headquarters of the Radio Corporation of America. The tower, clad in Indiana limestone, is at 70 stories and 256 meter / 850 ft the tallest of the complex. Its design by Raymond Hood - also known from

the American Radiator Building in New York, the former McGraw-Hill building in New York and the Tribune Tower in Chicago - was the basis for all future buildings at the Rockefeller.

To lure tenants during the Depression, all efforts were made to ensure efficient use of the available floor space. Thanks to the setbacks each office was assured of natural light. Other assets were fast elevators, air-conditioning and excellent underground connections to the subway.
The RCA building is now also known as 30 Rockefeller Plaza or GE Building.


Top of the Rock - the Observation Deck

The Rockefeller Center features an observation deck atop the GE Building with panoramic views of Central Park and the Empire State Building.

When the former RCA building opened in 1933 it featured a roof terrace designed as the deck of an ocean liner. Ventilation pipes were shaped as a ship's chimneys and visitors could relax in deck chairs. The observation deck remained open until 1986. By then the number of visitors had dropped while costs increased. At the same time the expansion of the popular Rainbow Room restaurant on the 65th floor cut off the elevator access to the roof, leading to the deck's closure.

Fortunately the observation deck reopened again in November 2005, finally giving the nearby Empire State Building's observatory some competition. After a renovation of some 75 million dollars, the art-deco style observation deck, promoted as the 'Top of the Rock' can be visited once again; only the deck chairs have disappeared.

A separate entrance at West 50th Street leads to the elevators. In the elevator, important historic events since 1933 are projected on the elevator's transparent roof.
There are in total three levels open to the public, including the roof terrace. The first is on the 67th floor and is completely covered.

The observation deck on the 69th floor has glass windshields while the 70th floor is completely open to the elements, offering visitors a fabulous 360 degree view.

Lower Plaza 

By 1940 Radio City, which became known as Rockefeller Center consisted of 14 buildings, located arounda central sunken plaza, the Lower Plaza. From the plaza you have a nice view of the sculpture of Prometheus and the GE building.

Ever since 1933, the famous annual Christmas tree lighting ceremony, which marks the unofficial start of New York's holiday season, has taken place here. The enormous tree, decorated with thousands of lights is installed in the area behind the Prometheus Statue. Around the same time, the sunken plaza is converted into a popular outdoor ice skating rink.

The plaza is connected to Fifth Avenue via a pedestrian street decorated with statues and flowers. This street is known as the Channel Gardens. The Channel Gardens are flanked by two six-story buildings with landscaped rooftops, the British Empire Building and La Maison Française. Another important building in the Rockefeller Center is the Radio City Music Hall. When built, it was the largest indoor theater in the world

with a seating capacity of around 6000. Guided tours give you the opportunity to catch a glimpse of the spectacular Art Deco interior.

A City in the City

Rockefeller Center - known as a 'city in the city' - is an exceptional example of civic planning. All buildings share a common design style, Art Deco, and are connected to each other via an underground concourse, the Catacombs. The complex is nevertheless well integrated in the city of New York, especially along Fifth Avenue. In 1959 and the early seventies, Rockefeller Center was extended with 5 additional buildings along sixth Avenue.

Flatiron Building

The Flatiron Building was constructed between 1901 and 1903 at the intersection of Broadway and 5th Avenue, at the time one of the most prominent sites. It is located near Madison Square at the end of the Ladies' Mile, one of Manhattan's most important shopping districts at the turn of the 19th century.

Not the tallest

The Flatiron Building was designed by Chicago's Daniel Burnham as a steel-frame skyscraper clad in white terra-cotta. At 21 stories and 307 ft (93 meter), it was one of the city's tallest buildings. It was not - as is often incorrectly thought - the tallest building in the world or even the tallest building in New York (these titles belonged to the Park Row building, built in 1899), but its singular shape and prominent location soon made it one of New York City's most famous landmarks.

The building probably featured on more postcards than any other contemporary building. Even the whole area, the Flatiron district, was named after the building. Originally the Flatiron building featured an observatory on the top floor, but taller buildings have taken over this function. It is still however a popular tourist attraction, and one of the most photographed landmarks in New York.


A Flatiron

Built as the headquarters of the Fuller Construction company, the skyscraper was meant to be named Fuller Building. But the building was soon dubbed 'Flatiron' after its unusual shape, caused by the triangular plot. Even though the plot is a right triangle while a clothing iron is an isosceles triangle, the name stuck and the building was officially renamed Flatiron Building. The Fuller company built another Fuller Building in 1929.

Burnham's Folly

The Flatiron Building was given another nickname: 'Burnham's Folly'. Many people at the time thought Daniel Burnham's triangular design combined with the building's exceptional height would not withstand strong winds. Some were even speculating how far the building's debris would spread after falling over. Last time I checked the building was still standing.

Empire State Building

More than any other building in the world, the Empire State Building represents the ambition of humans to build towers that reach for the skies. It probably is New York's best known building and is prominent on many postcards. 
  
The Empire State Building also features in many films, but the film that made it even more famous then it already was, was the classic King Kong in 1933. Even today, though the building has been stripped from its title of the world's tallest building, it is a symbol of New York itself visited by 2 million people each year.

8th World Wonder

At the time when it was built in the early 1930s on Fifth Avenue, the Empire State Building broke all records and was dubbed 'the 8th world wonder'.
The building had 64 elevators (now 73) and was constructed in only 1 year and 45 days. The skyscraper towered over the neighborhood with its height of 381 meter (1250 ft). As the Empire State Building was one of the last skyscrapers built before the Great Depression hit the real estate market, it wouldn't be topped until 1972, when the twin World Trade Towers dethroned the Empire State Building as the world's tallest building.  

Construction

The Empire State Building is built on a full city block. Much of it was occupied by the Waldorf-Astoria Hotel, which opened in November 1897 as the city's largest hotel with 1050 rooms. It was one the most prestigious in New York and attracted an upper-class clientele. At the end of the 1920s however,

the grand and plush design of the hotel had gone out of style and Waldorf-Astoria decided to build a new, larger hotel uptown.

After the site was cleared, construction started March 17, 1930. Thanks to an efficient design and standardized work - similar to an assembly line - the building would rise at an average of about four and a half floors a week, faster than any other skyscraper at the time. The building was officially inaugurated on May 1, 1931 in the presence of governor Franklin D. Roosevelt.

Design

The Empire State Building was designed by William Frederick Lamb of the architectural firm of Shreve, Lamb, and Harmon. Lamb, influenced by Raymond Hood's Daily News building, came up with a fairly simple design, defined by requirements such as the budget, time limit and New York City's 1916 zoning law. The building would have a classical composition of a 5 story base, a large tower with setbacks (required by the city's zoning law)

and a monumental spire. The limestone facade had little or no ornamentation.
What makes the design so great is that for all its simplicity and sheer bulk it has a perfect composition and massing, giving the building a certain grandeur.
 
Spire

The building is topped by an enormous spire. It was designed as a mooring mast and would enable dirigibles such as zeppelins to anchor at the top of the building so that passengers could embark or disembark. This proved to be very unpractical however due to the instability of zeppelins and after the Hindenburg disaster in 1937 the idea was shelved.

Great Depression

The Empire State Building was one of the last skyscrapers completed in New York before the Great Depression hit the real estate market. Demolition of the existing building at the site started just weeks before the stock market crash of 1929. After 1933 - with the construction of Rockefeller Center - no tall skyscraper would be built in the city for almost two decades.

As a consequence the Empire State Building held its title of the world's tallest  building for more than 40 years. But the Great Depression also caused a collapse in the demand for office space. The owners had such a difficult time leasing office space that the building became known as the 'Empty State Building'. It would take until the end of the 1940s before the real estate market was fully recovered and in the early 1950s the Empire State Building even became the most profitable building in New York City.

Observatory

You can visit the Empire State Building's observatory on the 86th floor from where you have a magnificent view over the city of New York.
The Empire State Building is situated south of Midtown, away from the skyscraper clusters in midtown and in the financial district downtown, so this is one of the few places in Manhattan where you have an open 360 degrees view. For the best view of the Empire State Building however, you better go to Rockefeller Center's observatory.

Daily News Building

The Daily News Building was constructed when the New York newspaper had the highest circulation of any newspaper in the world! 

 

The Construction

Located on 42nd Street, the Daily News Building was constructed in 1929-1930 for the newspaper

of the same name, owned by Joseph Patterson.
Journalist/publisher Patterson chose architect Raymond Hood for the job. Hood had designed the magnificent Chicago Tribune building, which was owned by Patterson's grandfather, Joseph Medill.

The 37-story Art Deco building, which stands 476 feet tall (145m), is best recognized by its vertical strips of windows separated with red and black brick patterned spandrels (the portion of wall between the top of one window and the window sill above it). White brickwork forms the separating vertical piers. (While most buildings of the time were being constructed with limestone,Hood decided it was too expensive so favored brick instead.)

The tops of the window stripes are decorated with ornamental spandrels extending all the way to the top of the building. At that point, they're sloped inward and split by a narrow pier.

The top of the building is flat; unusual for buildings of its time. However, the level top served as an inspiration for many skyscrapers that followed.

The main entrance is particularly indicative of the Art Deco style, with an ornate bas relief over that entrance featuring images of office workers underneath a sunburst.

Visitors will notice that the ten-story base of the building is larger than what is above.
The building was designed that way in order to accommodate the newspaper's large presses on the lower floors.

An addition to the Daily News Building was made in the late 1950s by architects Harrison and Abramowitz, including a five-story wing for the newspaper's enhanced printing plant and an 18-story wing to the east, which provided more office space. The newspaper moved out of the building in 1994 and the landmark skyscraper is now known as the News Building.

The Interior

Probably even more famous than the building's exterior is the giant globe that sits in its lobby. When the building first opened, it was one of the city's prime tourist attractions. The rotating globe sits in the middle of a domed room that's decorated with black glass. The map is updated as necessary. Clocks and thermometers line the walls near the globe, providing visitors with info about cities throughout the world.

Citigroup Center

At 915ft / 279m, the aluminum and reflective glass clad tower known as the Citigroup Center is one of the tallest building in Midtown Manhattan. But what really makes this skyscraper stand out are the triangular rooftop and the four massive 114ft (35m) columns on which the building seems to float. 
 
The Plot

CenterThose columns were the result of an agreement between Citibank and the St. Peter's Lutheran Church. The church owned a valuable property in Midtown, occupying one third of a city block on Lexington Avenue and 54th street. In the 1960s the church faced financial problems and wanted to sell its property.
At the same time Citibank, which was located just across the street, was looking to expand. Thus the church sold its property to Citibank, but only on the condition that the bank would build a new church replacing their 1904 Gothic Revival church. The two parties also agreed that the new St. Peter's church had to be a distinctive building, not incorporated in the office tower.

A Building on Pillars

As a result, the architects faced a problem: they needed to build an office tower on the block while at the same time providing enough space at the base for the construction of a church building. The solution was raising the building on four tall columns and a supporting core. The columns were placed at the

center of each side rather than at the corners. This way, the design opened enough space in the northwest corner for the new St. Peter's Church.

After the purchase of the property of the St. Peter's church, five more years were needed for Citibank to buy the rest of the block. The purchases were done by different companies since property prices would rise dramatically if the owners found out a large bank planned to develop the site. Construction of the tower started in 1972 by Hugh Stubbins & Associates, assisted by Emery Roth & Sons. The skyscraper opened in 1977 as the Citibank Center. With the company's expansion, the building was first renamed Citicorp Center and later Citigroup Center.
 
The Advent of Postmodernism

The Citigroup Center was the first tower in Manhattan that parted with the then prevalent Internationalist Style. Instead of a flat top, the designers gave the building a distinctive angled roof line. The original plans to construct setback penthouses on the roof were abandoned due to zoning restrictions. It was then intended as a solar panel, but never used as such. The rooftop now houses the building's

mechanical equipment, including a computer controlled tuned mass damper. This 400 ton block of concrete slides on a thin layer of oil. The inertia of the damper reduces the swaying of the building by up to 40%.

The construction of the Citigroup Center revitalized the area and several office towers were built in its vicinity. The most notable of these is probably Philips Johnson's nearby postmodern Lipstick Building.

The Plaza

The Citigroup Center includes a large sunken plaza and a 7 story atrium at the base of the tower with three stories of restaurants and shops. The plaza and atrium are directly accessible from one of New York's busiest subway stations.

Chrysler Building

At the beginning of the 20th century, the race for the tallest building in the world started and the Chrysler Building was the first building to top the then tallest structure, the Eiffel Tower in Paris.

New York would keep the tallest building in the world until 1974, when the Sears Tower was built in Chicago.
 
A race for the tallest building 

For Walter P. Chrysler, from the car manufacturer, building the tallest building in the world was a status symbol. The Chrysler building was in a race with the Bank of Manhattan for obtaining the title of tallest building in the world. It looked like the Bank of Manhattan would win the race, with an expected height of 282 meter (927ft) against around 230 meter for the Chrysler building. But the spire of the Chrysler building was constructed in secret inside the tower.

Just one week after the Bank of Manhattan had reached its top, the spire of the Chrysler building was put in place, making it 318 meter (1045ft) high, thus beating the Bank of Manhattan as the tallest building in the world. It would not keep this title for long: one year later the Empire State Building was erected.
 
Art Deco 

The Chrysler building is one of the last skyscrapers in the Art Deco style. The gargoyles depict Chrysler car ornaments and the spire is modeled on a radiator grille. Since it was restored in 1996 it glitters again like it must have in the 1930s.

And the building's Art Deco interior is even more magnificent than its exterior. The marble floors and many Art Deco patterns such as on the stylish elevator doors make the Chrysler Building one of New York's most beautiful office towers.

Popularity

The building's design by architect William van Alen was largely dismissed by contemporary architecture critics, who claimed the spire's design was kitsch and the tower nothing more than a folly.

But ever since its construction the popularity of the building has grown constantly, both among New Yorkers and architecture critics. It is now regarded as one of America's greatest buildings, and the Chrysler Building is often on the cover of architectural books and magazines.

Chanin Building

One of New York's most stunning Art Deco buildings, the Chanin Building uses a number of different materials in many inventive ways. 

Centrally located on East 42nd Street near the Grand Central Terminal, the Chanin Building was constructed between 1927 and 1929 for noted developer Irwin Chanin by Sloan and Robertson architectural firm. One of the tallest buildings of its time, it contains 56 floors and stretches to a towering 680 feet.

Irwin S. Chanin

The Chanin Building was seen by some as an example of the American Dream. A mere 20 years before the completion of this massive skyscraper, the developer, Irwin S. Chanin, an engineer who had worked on the construction of New York's subway, decided to get into the construction business. With only 200$ and some additional funding he started building small houses in Brooklyn. Soon he would expand into the construction of hotels, theaters and apartment buildings, amassing a fortune in the process.
Irwin Chanin himself saw the Chanin building as an 'architectural beauty wedded to business efficiency' and advertised the skyscraper in brochures as an icon of progress.  

The Building

Typical of New York skyscrapers of its era and in conformance with old NY zoning laws, the building is set back from its limestone base in a series of narrow setbacks that extend for the first 30 or so floors.

The soaring tower is made of buff-brick and terra cotta with limestone buttresses at the base and crown. The façade introduced the use of colored glass, stone, and metal on the exterior of New York's tall buildings. 

 

The Crown  
The Chanin Building is topped by a distinct art-deco style crown, consisting of a set of buttresses. At night, the top was reverse-lit by floodlights, creating a magnificent illuminated pattern, visible forty-five miles - more than 70km - away.   

Decoration

While the tower is a wonderful addition to the skyline, the Chanin Building's most wonderful contribution to architecture is its lovely ornamentation, both inside and out. On the exterior, a band of terra cotta features graceful leaf-like forms that are simply lovely. Also, a beautiful bronze frieze at street level depicts what seems to be the beginnings of the theory of evolution.
Angular zigzag patterns overlaid with curving flower petals are also found over the storefronts.


Interior

The two lobbies inside the building are equally as spectacular. Chanin designed them with the assistance of artists Jacques Delamarre and René Chambellan, the latter well-known for his architectural sculpture pieces. It is said that Chanin wanted to portray the opportunities available in New York, including to people like him. One lobby is dedicated to "intellectual" pursuits while the other demonstrates "physical" pursuits, both decorated with plaster figures that are rather cubist in style.

The ornate elevator doors from the main lobby sport a goose motif and once led to the top floor, where Chanin's office was located behind a set of bronze gates that were said to represent the greatness of the city. Beyond the gates, Chanin's office was also decorated with beautiful Art Deco ornamentation.

There was also an open air observation deck on the 54th floor and an ornate movie theater on the 50th, neither of which is still open.

American Radiator Building

Something Different 

For Raymond Hood, what started out as a small job designing radiator covers became so much more. When the American Radiator and Standard Sanitary Company decided to build a new showroom and office building on 40th Street near Fifth Avenue, the company turned to the man who had been creating their radiator covers and asked him to come up with a design for their new headquarters. Just a few months prior, Hood had become instantly famous for his unique winning design for the Chicago Tribune building and American Radiator was just one of many companies that pursued his talents.

Hood didn't let them down. The result was a 23-story, free standing mid-block office tower that was like nothing else in the Bryant Park neighborhood... or in all of NYC, for that matter. Hood's design, which called for a black brick exterior, was far different from the stodgy brownstones that were prevalent in the area. Hood explained that he chose the black brickwork to "lessen the visual contrast between the walls and the windows and give the tower an effect of solidity and massiveness". The result was stunning.
The tower is neo-Gothic as is the magnificent bronze and marble entryway. Other aspects of the building are more akin to Art Deco, a style that would take the world by storm by the middle of the 1920s. Gilded terra cotta ornaments crown the tower. The four-story base features bronze plating and black granite. Bronze carved allegories sit at the top of the base.

Inside, the lobby was decorated with mirrors and black marble. The basement once held a large showroom, where the latest in boilers and furnaces were displayed to the buying public.

The American Radiator Building was officially declared a New York City Landmark in 1974. It was later sold to the American Standard Company and then a Japanese firm called Clio Biz. In the 1990s, British Architect David Chipperfield transformed the building into the Bryant Park Hotel, a charming boutique establishment.

The History of 40 Wall Street

Now known as The Trump Building, the magnificent structure at 40 Wall Street was once in a race to be the Tallest Building in the World.

In 1928, developer

 
George Ohrstrom began amassing parcels of land so that he could realize his dream of building the world's tallest skyscraper. This commercial building was to be the headquarters for the Bank of Manhattan Trust Company and would be designed by H. Craig Severance, whose former partner William Van Alen was - at the same time - working on plans for the famed Chrysler Building.

Demolition and foundation-laying began in late 1929, taking just three weeks to complete - an astounding feat in itself. Motivated by the need to trump the Chrysler Building, workers completed the entire steel frame of the 72-story building in just 93 days and finished the project by May 1930, about a year after construction began.

For a brief time, Severance and partner Yasuo Matsui thought their building was the tallest in the world, until Van Alen revealed

plans for the needle-like spire atop the Chrysler Building, instead making that building the tallest.

About the Building

Even though 40 Wall Street lost its title as the Tallest Building in the World, it did indeed become known as "The Crown Jewel of Wall Street", and has long dominated the skyline in Manhattan's Financial District. Its pyramid-shaped crown and gothic spire are easy to spot from various locations in New York and New Jersey.

40 Wall Street's beautiful bronze doors, topped by the sculpture "Oceanus", make for a grand entrance into the ornate interior, which includes a bank boardroom modeled after the Signer's Room in Philadelphia's Independence Hall, and a magnificent two-story marble banking hall with world-renowned murals by Ezra Winter, whose work is featured in Rockefeller Center and many other NYC locales. The building became known for its 70th floor observatory and its 43 high-speed elevators.

A New Owner

After many years of struggle and low occupancy rates, caused in the early days by the Depression and World War II, the building switched owners several times and was even at one time owned by Philippine president Ferdinand Marcos.


In 1995, Donald Trump purchased 40 Wall Street and completed millions of dollars in renovations. He had hoped to make it half-residential/half-commercial, but the building remains entirely commercial. Trump attempted to sell the building in 2003, but there were no takers that could match his asking price of $400 million.

 

 

 

 

 

 

 

Redefining New York City's skyscrapers

Architect David Childs lost a colleague in the attacks of Sept. 11, a calamity he watched unfold from his office nearby. Mr. Childs, tapped almost two years later to design the signature skyscraper at the new World Trade Center, had that memory always in his mind as he grappled with a conundrum that has bedeviled construction professionals over the past decade: how to build an office tower that is safe and secure yet doesn't look and feel like a bunker, and that is economically viable.

“It had to be a proud gesture to our resilience,” said Mr. Childs, a consulting design partner at Skidmore Owings & Merrill. “It had to be a great place to work, and it had to be safe.”

One World Trade Center must be worthy of its place on the skyline, and serve as a symbol of the city's rebound from tragedy and as a marker for the nearby memorial. And, given its inevitable allure as a target, the 1,776-foot tower must be among the safest skyscrapers in the United States.

The attacks changed how New York's prominent office towers are designed, built and protected. Police, fire officials and security experts now play a role, working alongside architects, developers and engineers. Together, they have forged a new paradigm for safety that employs both physical and psychological tools.

Though property owners are reluctant to go into detail for fear of providing blueprints to terrorists, some elements of the new normal are plainly visible: 3-foot-high bollards ringing major towers, platoons of security guards and a plethora of cameras and X-ray machines. Others are less obvious: cores and columns composed of extra-thick, steel-reinforced concrete; backup sprinkler systems; and acres of shatter-resistant glass.

In the aftermath of the disaster, developers found few answers to questions about what changes should be incorporated into design. The city's building code, which hadn't been updated since 1968, provided no help.

Planning process transformed

When Larry Silverstein, who leased the World Trade Center from the Port Authority of New York & New Jersey, began planning a replacement for 7 WTC, he called in Mr. Childs and a team of engineers, as well as police and fire officials. Many of the features they used were integrated into the building code, which was updated in 2004, and then into other high-profile properties.

Among the crucial enhancements at 7 WTC: Elevators, emergency stairs and mechanical systems, located in the building's center, are wrapped in a 2-foot-thick, steel-reinforced concrete shell. Before, such core elements were often enclosed with drywall and rebar and in some cases were even on the building perimeter.

The tower's core also includes “repeaters,” devices that let emergency responders communicate during a disaster—something they were unable to do on Sept. 11. Similarly, to help prevent the gridlock as firefighters race upstairs into a stream of fleeing tenants, the staircases at 7 WTC are 66 inches wide, 20% wider than the building code requires. There's also a system to suck smoke out of stairwells, and strips on each stair that glow if the building's three systems that keep the lights on fail.

To protect the building from a bomb blast, the glass panels in the four-story lobby are treated to bend rather than break.

High-profile projects elsewhere in the city also must balance security and aesthetics.

“You don't want to create architecture that gives in to fear,” said Richard Cook, a partner at Cook+Fox Architects, which designed the Bank of America Tower at One Bryant Park. “Our idea was to create a transparent building that focuses on nature and had a clear view of the park,” he said.

The tower is surrounded with 149 stainless-steel, yard-high bollards placed about every five feet along the curb. Light flows through specially treated glass into a soaring, 43-foot-high lobby, whose support columns can bear the extra weight if one becomes damaged.

“I think the building still feels open and airy,” said Vishaan Chakrabarti, director of real estate development at Columbia University's Graduate School of Architecture, Planning and Preservation. “I didn't love the bollards, but I've gotten used to them.”

There are other, nondesign security measures, including uniformed security guards and turnstiles patrolled by dogs. “So much of this is psychological,” said Louis Esposito, chief operating officer of The Durst Organization, co-owner of 1 Bryant Park. “You want the bad guys to know we are watching.”

Visible or invisible, security is expensive. Experts estimate that it can add 5% to 20% to construction costs, which can translate into hundreds of millions of dollars. For example, shatter-resistant glass is about $9 a square foot, 50% more than an untreated pane. Wider staircases and thicker cores eat into rentable space.

Extra effort, extra cost

Similarly, the lobby at 11 Times Square, the 1.1 million square-foot tower that opened in 2010, was made roughly 30% larger than it otherwise would have been to accommodate the turnstiles.

The bollards at One Bryant Park cost $16,000 each, and the building has a backup sprinkler system. “Is three better than two?” Mr. Esposito asked. “Yes, and four is better than three, but at some point you have to think of the building's economics.”

The need for safer buildings coincides with the city's effort to create inviting, lively streetscapes. For example, thoroughfares removed to make way for the original WTC are being reintroduced.

Despite any concessions, some wonder if security concerns influenced 1 World Trade's design to the point that it looks overly fortified, particularly at its base.

In 2005, the NYPD demanded that the tower design be changed to make it safer. It is now an office building sitting on a 187-foot-high concrete box with foot-thick, steel-reinforced concrete columns designed to bear up to 14,000 pounds of pressure a square inch—55% more than normal. It is also set back 40 feet from the street instead of the 25 feet initially envisioned.

One WTC will likely end up being a “forbidding presence,” wrote Blair Kamin, in his Pulitzer Prize-winning book, Terror and Wonder: Architecture in a Tumultuous Age.

Only when the building is finished in 2013 will we know if the designers succeeded in humanizing it, but Mr. Childs says he has improved the 2005 design. For example, the base will now be clad in glass rather than metal.

“The glass will create an openness,” Mr. Childs said. “It will reflect the people, the street, the trees.”

Still, creating that open feeling has had challenges. After spending about $6 million testing the prismatic glass Mr. Childs had hoped to use, the Port Authority realized recently that the material kept breaking. Now the architect is tweaking the design to use a different type of glass.

“We're hoping it will be as close to the original design as possible,” a Port Authority spokesman said. “We hope it will still be beautiful and distinctive.”