The project originated from an initiative by the Lutheran church of St. Peter's (the "jazz church", where the memorial service for Louis Armstrong was held), which was interested in selling its property on the western portion of the block. First National, which had its headquarters in the 399 Park Avenue on the adjacent block right across Lexington Avenue and was in need of expansion, set to acquire properties in 1968, including the church site, which was purchased in 1970.

Five years later the needed individual sites were bagged for the fantastic total sum of $40 million ($9 million for the church plot) and the construction of the Citicorp Center began in 1974. (The only building left intact on the block was the 880 Third Avenue from 1965, at the south-eastern corner, due to its relatively young age.)

One of the seven initial designs featured two separate towers, one housing the office space, the other an elevator and service tower. Despite the availability of a thus completely free interior space, the design was changed to the more traditional, integrated arrangement in order to attract traditionally-inclined tenants and to cut down on the structural expenses of the scheme.

The 59-storey tower rises to 279 m, and when completed, it raised controversy because of its 50 m high sloping top (image) -- originally designed to house 100 luxury condos, set back in a slope configuration, although the execution of a residential plan was eventually denied by the city officials as the zoning change fell through. The top was then planned to be used to accommodate experimental solar panels connected to air-conditioning equipment; the ambitious installation was never installed (as another scheme of energy-consciousness, the elevators are double-decked, serving both even and odd-numbered floors simultaneously).

In addition to the mechanical and window-washing equipment, the tower top houses a Tuned Mass Damper -- in effect, a 360 metric ton, 9 times 9-meter concrete block on an oiled plate moved by computers -- that lessens with its inertia the sway caused by strong winds to about half. Strong winds are a constant enemy of high buildings, especially those standing on stilts: there are four 10-storey pillars under the middle of each facade (22 m from the corners) and a large center core for elevators etc. The tower stands on its "feet" 40 m above the street level.

The, obviously, novel structural system consists, along with the bold support pillars, of diagonal braces on the outer walls -- which are totally unnoticeable from the outside . These act both as structural bracing and to transfer the loads to the four perimeter pillars. The structural system underwent a hectic strengthening a year after the building's completion due to a savings-conscious substitution of originally-designed welding attachments to bolts. In the event of the rare, but nevertheless not impossible hurricane-strength winds the building could have otherwise toppled.

The buildings of the center (except for the church), as well as the atrium interior, are clad in aluminium plating, including the bottom of the tower. The tower itself has a uniform facade treatment of alternating bands of alumium plating and window stripes, with the top completely clad in alumium. The 165,430 m² building houses 93,000 m² of office space within.

The seven-storey, 21,000 m² shopping center, "The Market", is located under the looming tower and has a 25 m high skylight- illuminated central atrium with surrounding shops and restaurants. One of the tower's support pillars rises from the patio of the atrium space and through the roof, flanked by the set-back balcony levels of the atrium's east wall.

The new St. Peter's Church (619 Lexington Avenue) is located on the patio outside the Citicorp Center. The church is a polygonal design clad in granite and decorated by sculptor Louis Nevelson, and still continuing the tradition of regular free jazz concerts for public.

Next to the church, in the space vacated by the pillar-supported tower, is a sunken plaza, one of the last before the revised regulations. The regulations were, in fact, the impetus behind the choice of the novel support method for the tower, as well as the re-building of the church. See Forum thread. The plaza connects to the inside atrium and the church, as well as to the subway station.

After the 1998 merger with Travelers Group, the center was accordingly named the Citigroup Center.

In April 2001, Boston Properties acquired the building for $735 million, as it did with the 399 Park Avenue a year later.

In the summer of 2002, as a result of an exponentially increased possibility of a terrorist attack, the 53rd Street side pillar was strengthened with blast shields of steel and copper as well as steel bracing.

The original developer of the site -- located across the street from Metropolitan Museum of Art at Fifth Avenue, and between two historic buildings, a tall neo-Classical palazzo (by McKim, Mead & White, 1911) and a Beaux Arts apartment house (1903) -- managed to tear down its occupants, two old town houses, before the firm went bankrupt.

Kalikow Co. then took over and hired Philip Birnbaum to design an apartment tower to the site. Due to the planned building's existing surroundings, public outcry resulted over the plans, and after lengthy processing Johnson & Burgee were hired to especially re-design the Fifth Avenue facade to suit the surroundings.

The base of the 23-storey building follows the rusticated austerity of the neighbouring palazzo, with the upper facade split by a series of glass-walled vertical shafts and protruding horizontal ornaments "extending" from the building next door. The facade facing Fifth Avenue is clad in limestone, while the other facades are of buff brick.

After the Landmarks Preservation Committee rejected the original, flat-top design, a tapering, fake mansard roof -- merely a wall facing the street -- was added, getting its influence from the Beaux-Arts neighbour.

The building incorporates 76 co-op apartments, many combined from smaller units.

Built to a midblock site to the west of the notable Park Avenue fixture, the Racquet and Tennis Club (McKim Mead & White, 1916), a palazzo of Florentine Renaissance style, it rises over its five-storey neighbour with unblocked views of the avenue and the Seagram Building across.

In their bid to obtain air rights from the club, the developers were originally unsuccessful, but when the city not only granted the development 18,500 m² of extra space as a public space bonus but also a Park Avenue address -- in effect making the air (and address) rights less crucial for the developers -- the club publicized what was most probably a Trump-like scheme to turn the tables. Plans for a 38-storey hotel on the club's site, partly above the club itself, and blocking the Fishers' building's views, were announced in March 1978 (on the same day that the chippendale (ex-)AT&T Building, itself also using the galleria bonuses, was announced). After that, and with the deadline for a public hearing on their building approaching, the developers made a deal about purchasing the air rights, undoubtedly one more profitable for the club.

The 45-storey building's lower portion, featuring an indoor atrium, is visually restrained. Above that, the building follows the visual cues of the Lever Building to the north, with its green-tinted glass wall. The plan has no less than 15 corners, in a sense a triangular prism with diagonals facing Park Avenue, the sharp edges cut off and triangular vertical grooves carved into these faces. The building rises unsetback to the top at 175 m.

Housing 98,900 m² in all, the floor sizes range from 2,740 to 4,090 m² per floor and can accommodate up to 12 corner offices due to the shape of the plan. 25 elevators serve the building.

The glass-walled indoor public arcade extends through the block and features artwork in the Chartwell Gallery, trees and a waterfall as well as a Starbucks (no surprise there) and escalator leading to the second floor mezzanine and office lobby. The double-height space has inlaid granite floor paving and a ceiling with a thin grid pattern. The monolithic elevator banks are clad in dark marble.

In a July 2002 deal, the insurance company Aon leased 25,000 m² of space within the building, with the building also renamed Aon Plaza.

The building rises on a site once occupied by the Architects Building (Ewing & Chappell and La Farge & Morris, 1912), built to accommodate architects' offices and exhibition spaces (image).

Except for an elevated plaza facing Park Avenue and 40th Street, the 119,400 m² building abuts plot lines along its six-storey base. The 49-storey tower has a curious split-octagon plan, with the northern half of the form being shifted towards Park Avenue. At the top at 191.5 m, two-storey notches cut to tops of street-side facades split the form further. The whole building is clad in a a curtain wall of dark-tinted glass and dark aluminium.

The main entrance to the building is located at the diagonal part facing the gray granite-clad plaza with a fountain. Furthermore, the Park Avenue sidewalk between 40th and 41st Streets features 20 bronze relief plaques measuring 55 x 91 cm, depicting notable buildings in the vicinity.

The four-storey lobby has a large slanted glass skylight ceiling (image) that is supported on the outside by four oval-shaped granite columns. The gray granite paving extends to the interiors and the elevator bank walls. The 41st Street entrance at a lower level is connected to the elevator bank via escalators. Lobbies include ground floor retail spaces as well as the entrance to the Club 101 private/executive dining club and meeting space.

Office floors range from 2,160 to 4,230 m² in size and are served by 25 elevators. The plan of the tower offers "only" eight corner offices, not quite beating the Park Avenue Plaza's 12... Two basement garage levels accommodate 100 cars.

The building features an energy-saving installation consisting of a basement chiller plant supplying 1.9 million liters of ice slurry (generated with off-peak hours electricity) that is designed to cool the building down in daytime.

As the plot was being assembled, the owner of a single site on the 54th Street side, housing the Reidy's restaurant, refused to sell the property. As a result, the skyscraper was built around it, and the restaurant now protrudes as a holdout from the skyscraper mass. It took 24 months from the start of construction to the full occupancy of the office spaces.

The 43-storey building has a facade of polished red granite and brown-toned glass. The base of the building has a set-back on three sides of lower floors that diagonally tapers from the plot lines, before the shaft rises vertically to the top at 176 m. The top is stepped in a series of terraces facing Madison Avenue.

The austere lobby has pink granite paving extending to the walls of the elevator banks. The John Becker Gallery within features art exhibitions. There is also retail space and two restaurants. The 96,100 m² of rentable space within the building is served by 22 elevators and houses also the headquarters of its developer, Tishman Speyer Properties.

The vest-pocket-sized plaza next to the recessed 53rd Street entrance is enclosed in granite walls; the flanking wall opposite the entrance incorporates a waterfall installation, with a freestanding 6-meter section of the torn-down Berlin Wall on display, doubling as a graffiti artwork. A sidewalk clock is located on the tree-lined Madison Avenue side.

The austere style of the building follows the International Style with hints to Classicism, with the curtain wall giving way to masonry motifs.

The light grey granite exterior consists of two differing facade types, facades on opposite sides being similar. The facade facing Park Avenue (as well as the opposing side) has heavy columnwork base, main facade being vertically accentuated by pilasters. The 42nd Street side has a tall colonnade creating a sheltered bay, the facade having horizontal bands of windows. There are openings at the top, with the street level columns continuing through these.

On the ground floor, there is a public garden, a café and an annex of the Whitney Museum of Modern Art housing temporary exhibitions.

Built next to the venerable jewellery store of Tiffany & Co., the building used the air rights of its older neighbour, as well as utilized the bonuses offered by the Fifth Avenue Special District zoning. (Trump even originally contemplated naming the building Tiffany Tower.)

The co-operation between Scutt and Trump, the developer behind several NYC projects, was a result of Trump's impression in the style that Scutt had shown with the "crowned" design of the 1 Astor Plaza, making it distinguishable from the glass-box designs of that day.

The building was the tallest concrete-framed tower in the city at the time of its completion. The 68-storey tower has a facade of dark-tinted glass, rising to the height of 202.5 m over Fifth Avenue. The corner of facade facing the intersection of Fifth Avenue and 56th Street is sliced off in a series of setbacks (forming a sort of hanging garden and place for festive displays), with the corner above that broken diagonally into a series of sawtooth edges running to the top.

The bottom six floors of the building consist of shops and restaurants surrounding an atrium, decorated with glowing rosy-pink marble and shiny brass, the whole crowned with a five-storey waterfall and a skylight.

The next twenty storeys are for offices (Trump's own office is on the 26th floor), and the top forty storeys are occupied by a total of 266 luxury apartments, all with views on three side -- and many of them housing multimillionaires. The entrance to the apartments is from 56th Street, whereas the office elevators are located in the main lobby.

Trump himself has a modest (characteristically) fifty-three-room penthouse apartment with a surrounding rooftop garden on the top. (The apartment was used as a filming location in the film The Devil's Advocate (1997), representing the home of a triple-homicide suspect real-estate developer (!).)

The company had, in fact, already had activity at the same address, such as housing a showroom for its "business machines", designed by Eliot Noyes in 1955.

The 184 m tall building, in the shape of a five-cornered prism, has its diagonal facade facing south-west. The 41-storey exterior is clad in polished red granite, alternating with continuous stripes of blue-green-tinted windows.

The entrance to the lobby is through the north-east corner that has been sliced off diagonally as a cantilevered structure, with the corner of the building looming overhead. The slice-off cost approximately $10 million to realize structurally. The granite paving on the outside extends into the lobby itself. Michael Heizer's sculpture Levitated Mass (1982), an engraved flat stone laying inside an angled pool of stainless steel, stands in front of the entrance.

The building incorporates the Garden Plaza, a part of a through-block arcade connecting 56th and 57th Streets and the IBM with the neighbouring Trump Tower. The spacious, 930 m² greenhouse-like glass atrium has a zig-zag roof of alternating diagonal and vertical panes, and it houses full-sized bamboo trees within, although many of the original number of eleven have been removed to accommodate contemporary art installations by the Pace Wildenstein Gallery.

The building also originally had the IBM Gallery of Arts & Sciences, a museum and art performance and exhibition room next to the lobby, but the gallery was later closed. The space has been occupied by Freedom Forum's media museum Newseum.

Although IBM sold the building to the developer Edward J. Minskoff and Teachers Retirement System of Ohio in 1994, it has retained a sizable portion of the building in its use. In Feb. 2003, the company renewed the tenantship deal to continue after 2004 -- the company will remain on eight floors of the building.

Work on the building started in 1978, and from the beginning this 38-storey building created heated debate both for and against. The city agreed to allow the vertical massing of the building as a zoning remission against the public amenities in the form of open-air gallery spaces, as well as AT&T's promise to retain its activities in the building well into the future.

To make this 197.5 m tall building look more monumental, Johnson topped it with the unique, curving post-modernist "chippendale" forms. Like his work on the Seagram Building for International Style, also this building was a model for a new style for others to follow.

The building is clad in grayish-pink granite from the same quarry that supplied the facade facing for Grand Central Terminal.

Structurally, the building employs tube frame in its framework, with the tubular columns tied with trusses at the top and bottom.

In accordance with Madison Avenue's identity as a shopping street, the actual building was lifted 20 m up from the street level, with only the minimalist central lobby, identified outside by the 24 m high arched bay, being actual building. From this vaulted, neo-Romanesque entrance lobby elevators take customers to the building's white marble main lobby above with 25 more elevators for reaching the upper floors. The elevators have bronze doors and their artwork was inspired by the Chrysler Building elevators.

At the street level, there were open galleries created under the building by the tall colonnades around the base and, behind the building, a 20 m high through-block galleria with a curving skylight. All these spaces have zig-zag-patterned granite mosaic floor.

Despite the abovementioned promises to the contrary, a large portion of AT&T headquarters had already been relocated to New Jersey even before the building's completion, and in 1992 the Sony Corporation bought the building as AT&T moved its activities in Manhattan to the Sixth Avenue premises in TriBeCa.

In a remodelling by Gwathmey Siegel, the open galleries were subsequently enclosed as Sony retail spaces and the skylighted galleria -- originally presented for approval and zoning remission as an open-air throughway -- was enclosed and partly used up as a retail space with cafés as the Sony Plaza. Sony Wonder Technology Lab, a multimedia showcase for new products and technologies, is also reachable from the plaza.

In the course of the rebuilding, 980 m² (out of 1,310 m² total) of open arcade space was replaced by 560 m² of retail space and the covered arcade increased by 380 m² and enclosed. The "transaction" was approved on the basis of differing bonus ratios for public amenities.

A statue from the roof of the previous AT&T headquarters at 195 Broadway, the seven-meter Spirit of Communication (or "Golden Boy") by Evelyn B. Longman, was removed from the entrance lobby after the transaction and moved to AT&T's New Jersey premises.

Originally, the plot was assembled to house the new headquarters for the rival Lehman Brothers, but the depression of the mid-1970s forced a cancellation. Located on a trapezoid plot next to the Fraunces Tavern Historic Block in Downtown Manhattan, the 29-storey building utilizes its air rights to gain a bulk of over 90,000 m². Similarly, the brown stone facade treatment was a nod towards the landmark block.

With chamfered corners to the south, the building wall facing Stone Street (or its location, before its portion got de-mapped) to the north follows its curvature, with the lobby curving similarly. A result of the change to the street-plan was the granting of a landmark status to all the nearby street "grid".

Entrance to the building is through an archway and underneath a bronze plaque with the map of Lower manhattan as it was in c. 1660. During the excavations objects from the Dutch era were found and recovered before the construction work was started.

The building's main tenant is the Goldman Sachs investment bank.

Located along the East River waterfront in Downtown Manhattan, the 101,500 m² bulk of the $115 million tower was enabled by the transfer of air-rights from low-rises in the South Street Seaport Museum area.

The 41-storey building has an octagonal plan that is broken at the lower level by skirt-like extensions that expand from the main mass. The facades of the building are of dark-tinted glass throughout, a notable contrast with the neighbouring high-rises. The mechanical floors in the chamfered rooftop structure reach 169 m.

Entrance to the paved and landscaped interior arcade below the building's footprint is underneath the space-frame-supported skylight that rises diagonally from the corners of the extensions, in principal akin to the 101 Park Avenue lobby. The outer glass walls consist of similar lattice-work. The arcade interior surfaces, as well as the office building's columns extending through the space have a facing of warm-toned wood (link).

Among the amenities are the Center for Arts Education's The Gallery at 180 Maiden Lane, an artistic showcase for public school students, an auditorium and lecture halls.

The building was sold to The Moinian Group for $355 million in August 2004.

The 31-storey building consists of three intertwined masses; the core, consisting of twin cylinders joined by straight walls, is clad in a reflective glass curtain wall and reaches the height of 123 m. Flanking it, and two floors lower, are two offset rectangular masses with facades of horizontal bands of glass and pink granite cladding, leaving only the northeastern and southwestern cylinder corners of the core exposed.

The building features 55,000 m² of office space, with main entrance through the corner, underneath a curved canopy.

During the excavation work, an 18th Century British merchant ship, used to hold the old landfill in place, was discovered. After archeological studies, the bow portion was detached and moved to Newport News, Va. for restoration and display.

The 34-storey building is clad in gray granite and rises as an unsetback slab to 133 m. The mid-portion of the west facade is recessed, whereas the east facade facing the Seaport has the mid-portion protruding out of recesses between the three sections.

The main entrance is from John Street under a three-bay portal of glass (details). The lobby has a uniform, light-toned finish throughout and has on three walls large-scale artwork of colourful geometrical patterns (image).

There is 97,100 m² of space within the building, with floors ranging from 3,250 m² to 1,450 m² at the top floor including only the center portion of the slab. There are 20 elevators and a basement garage. The building also houses the Downtown TKTS office.

In October 2005, the NYC Office of the Comptroller leased 12,000 m² of space within the building, moving from 1 Centre Street.

Originally started as a development of Cadillac-Fairview, the building was acquired by Jaymont Properties as it was completed.

The exterior of the 173.5 m tall building forms a distinctive pattern of panels of polished red Balmoral granite from Finland alternating with window openings, clearly indicating the location of the outer wall diagonal bracing.

The concrete structural frame uses the off-center core (on the western side) and the outer wall colonnade, with its large-scale wind bracing, to form the 50 column-free floors with a total of 43,600 m² of rentable space. On the longer, avenue-facing sides the bracing forms a series of X's, while on the shorter sides the bracing zigzags through the facades. The structure won the Concrete Industry Board Annual Award in 1983. Each floor also has its own independent HVAC system.

On the Third Avenue front, the plaza is paved in red brick and granite, with a row of tress flanking the roadway.

The building incorporates, among other business-related facilities, a 154-seat auditorium as part of the largest office building conference center in Midtown Manhattan.

First proposed and outlined in 1976, the slender 52-storey glass tower was built to help pay for the extension and renovation of the museum -- presently the lower floors of the tower house museum exhibition spaces, expanding museum's floor area considerably.

This 198 m tall residential tower was constructed with 263 apartments and cost $55 million to build. The glass facade consists of variously tinted blue-green opaque glass and has a series of recessed terraces at the top.

At the moment there are plans for further expansion of the museum premises, also affecting the tower. Plans by the Japanese architect Yoshio Taniguchi include the extension to adjacent plots, removal of the glass atrium, as well as altering the south facade of the tower. The expansion is planned to be complete by 2004.

The 43-storey tower with brown brick cladding rises to 137 m and has a roughly L-shaped plan accented by the faceted protrusions of corner balconies, made of prefabricated brick elements. Along with living room strip windows, the balconies form horizontal striping around the diagonal portion facing the street corner at Second Avenue and 47th Street. The entrance is located next to this chamfered corner.

There are 133 luxury apartments and such amenities as a health club with swimming pool and a garage. The building lobby features the Gallery at Dag Hammarskjold Tower for contemporary art exhibitions.

The actual Dag Hammarskjold Plaza (link) to the east occupies a whole blockfront facing 47th Street between First and Second Avenues. It features, for example, the Holocaust Memorial Wall and a greenery named Katharine Hepburn Garden in 1997.

The facade of this 54-storey building consists of alternating bands of windows and limestone, interrupted by piers of brown granite. The tower rises to the height of 228.5 m through two setbacks, indicated by recessed bays on the north and south facades. The plain limestone top with its vertical granite striping forms the last setback and features an arched Romanesque window on both ends -- this houses the Equitable boardroom.

Included within the 142,660 m² state-of-art building is a 100-seat auditorium, a fitness club and several restaurants as an effort to attract tenants to this then professionally unfashionable part of Midtown. Similarly, the building was connected to the extensive Rockfeller Center underground concourse, and a renovation was undertaken in the eastern Equitable building on the Sixth Avenue side.

On the ground floor there is a through-block galleria as well as the Equitable (now AXA) Gallery for art exhibitions.

In 1986 Roy Liechtenstein enhanced the vast, skylighted entrance atrium with his large (22.3 x 10.8 m) Mural with Blue Brushstroke. Primarily a collage of his earlier works, the mural was sketched on the wall with the aid of slide projectors, and then painted.

Announced already in 1972, this hotel project was to restore some of the all-public nature of the old Times Square. Portman, an architect-developer, acted as a codeveloper also in this project, collecting no less than 90 percent of the financial backing.

Portman's first plan was in the form of two parallel slabs, connected only by five-storey bridges. By the time of the final plan he had incorporated his hotel architecture trademark into the design: an interior atrium, around which the rooms were grouped.

Originally to be completed in 1977, the hotel was realized only eight years later, after the financial and planning climate was favourable. As even the Special Theater District Zoning Amendment, introduced with the neighbouring 1 Astor Plaza, could not give enough bulk for the 50-storey building, a zoning remapping was granted, adding a 20 per cent overhead bonus, as well as height and setback variation and a permit for a 400-car public carage.

The struggle for the preservation of old theater buildings, however, led to the creation of the Theater District zoning area and renovation of the Forty-second Street Theater building by the developers as a "payment" for the zoning variances of the new hotel.

The entrance to the hotel is via the "caragelike" drivethrough and an austere street-level elevator lobby, with the main hotel lobby reachable by elevator, so the hotel isn't one of the most prominent outwardly -- except for the neon-signs (it's Times Square, after all) and the lit arches above the street entrances.

Indeed, in addition to the neon advertising signs, the hotel's less prominent appearance was a direct result of its location in Times Square. The less savoury neighbourhood of the 1970s and 1980s led to a design that provided ample blank walls and a guarded entrance from side-streets.

The hotel building incorporates, in fact, two atria: a smaller one within the base, around which the shops, restaurants and exhibition and meeting rooms (54, with 9,300 m² of total space), as well as the 400-seat cinema are grouped, and the 35-storey main atrium (image), rising from the 13th story lobby. A circular shaft with tracks on the outside for glass-walled elevators occupies the center of the atria and rises from the street level to the revolving lounge bar at the top. The base also houses a revolving lounge, with views to the street and lower atrium.

Hotel's musical theater is located to the Broadway side of the base, above the driveway, and has a capacity of 1,050. Also the theater is accessible from the hotel's street-level lobby by elevators of the elevator shaft.

The upper atrium has starlit trees and a large, rotating clock around its midfloor café. The 1,946 hotel rooms and 56 suites are located both in the north and south slabs as well as the connecting "bridges", supported by 34 m long trusses and set to different distances from the elevator shaft. The rooms are entered from the inside balconies and have views to both outside and to the atrium.

Although a part of the WTC in name, the Silverstein Properties-developed building, also known as the Tishman Center after its constructors, was on a separate ground lease and tax lot from the rest of the Center (see map). The building was built atop the power substation building that supplied much of Downtown Manhattan with electricity. To make matters worse, the foundations had to be built through the building avoiding not only the operational equipment there, but also the ramp serving the WTC and a subway line. Moreover, the WTC towers caused wind conditions that required special stiffening determined by computer-run wind analysis.

The resulting frame was divided into two distinct zones, with the first seven floors built around a stiffened central core that was connected through braced floor slabs to a wind truss system on the lower east and west walls. From seventh to the top, the braced outer wall was augmented by two two-storey "belts" against high wind forces. On the north side, the outer wall above the seventh floor up cantilevered two meters over the substation building, which required the installation of 20 m long tapering girders to be installed from the core to the outer wall.

As the existing foundations through the substation building were mostly not aligned with the perimeter colonnade of the new tower, they had to be fitted with concrete caps to allow transfer of loads to the foundations. For the core, the loads were transferred through a heavily braced foundation slab. 50 new foundation "caissons" were built, most of which had to be squeezed through the substation building.

Although not small by any standards -- built on Port Authority land, it was exempt from zoning regulations and could occupy the whole trapezoidal plot with no setbacks -- the building's 44 4,450 m² floors and height of 160 m were obviously dwarfed by its older twin brothers. The building's appearance and its alternating facing (horizontal glass striping on the Barclay and Vesey Street sides and red granite, holed by smaller windows, on the other two) set it apart also visually from the Twin Towers of the late 1960s.

The building was from the onset equipped with its own power substation for reselling of electricity to the tenants. After the 1993 terrorist attack in the World Trade Center, the mayoral emergency command center was built within the building, with its own power generators for emergency electricity generation.

In front of the building, on the WTC compound plaza level, stood Alexander Calder's 8-meter steel sculpture Three Red Wings as well as pedestrian bridges over Vesey Street from the WTC compound, with a round plexiglass tube covering (image) the eastern one.

The occupation of the building went through the same difficulties as its larger twin brethren. The investment bank Drexel Burnham Lambert (best known for its star dealer, the notorious "junk bond king" Michael Milken) was to become a tenant in 1986 but backed out in favour of the eventually ill-fated Boston Properties' go at the Columbus Circle; in 1988 Salomon Brothers finally relieved Silverstein with their lease of half of the ofice space.

The building collapsed during the terrorist attack on the WTC in September 2001, having been structurally weakened by the destruction of the nearby WTC towers. A theory strongly suggests that the large amount of diesel fuel for the emergency generators stored within the building (for the use of, for example, the Mayor's emergency center) could have created the heat that led to the collapse. Especially as none of the other skyscrapers surrounding the WTC were structurally fatally damaged.

New development on the site

The 52-storey building sports an all-black facing not unlike in appearance to the Trump World Tower next door. In fact, too much next door for the liking of many of the 100 U.N. Plaza residents, as the super-tall neighbour blocks the view to the U.N. complex.

The brick-clad shaft of the tower slab is set-back from the street and rises vertically with balconies on the corners and mid-portions of the north and south facades, until the eight top apartment floors, where its east and west facades taper shaply to form a top wedge. The balconies of these apartments protrude as horizontal "ribs" and extend around the corners of the slopes. The top triangle at 170 m houses the mechanical floors and heat exchangers.

The triangular theme of the top extends to the ground floor lobby with its triangular window arches -- being gold-trimmed inside the lobby and complemented with gold striping on the walls -- and pitched-roof entrance canopy, also gold-tinted, on the plaza side. There are 267 apartments in the building.

The landscaped plaza by Thomas Balsley Assocs. is located on the east side of the building, extending to First Avenue. In addition to fountains and greenery, the multilevel plaza consists of extensive brickwork extending to the sidewalks along both the plaza and the building.

The building is located next to the Citicorp Center, with an equally "angled" appearance and an aluminium facade with horizontal stripes of windows. All the window stripes have the upper half consisting of light blue "shades" above the open window panel.

The main shaft of the 47-storey building is rectangular, with a triangular portion on the Lexington Avenue side pointing to the street, the top of the building at 199 m is in the shape of a triangular prism pointing to the opposite direction.

Cantilevered under the diagonally sliced-off corner on the Citicorp side -- providing an open view along Lexington Avenue to the Center -- and set behind a single round column is the entrance to the lobby, with all-glass walls facing building's triangular plaza. The lobby has banded white marble decor in the vein of Italian Renaissance as well as artwork Salto Nel Mio Sacco (1985) by Frank Stella.

The paved plaza has, similarly to Citicorp Center's, an entrance to a subway station, in this case a stairway covered with a slanted glass canopy consisting of large panes.

The 77,100 m² building uses the air rights of the adjacent City Center for the Performing Arts (arch. Harry P. Knowles and Clinton & Russell, 1924). This glass tower of a primarily octagonal plan has streamlined extension wings that set back along with the gradual decrease of the central octagon's diameter. The octagon has a vertically accentuated glass facade, while the wings feature horizontal strips of glass and marble. The tower ends in a domed top at the height of 248 m (the dome being a nod towards the City Center building).

As a residential tower, the building uses a concrete structural system, being at the time of its completion the second tallest concrete-framed skyscraper in the world.

The two lobbies (for the residential and office sections of the building) are lavishly decorated with marble and wood. The bottom 23 floors of the tower are for commercial use and above it there are 353 luxury apartments, growing in size the higher they are. At the top there are two 200 m² apartments. There is also a health club for the tower residents.

Standing alongside the Carnegie Hall Tower and the Metropolitan Tower, these buildings form the tallest group of skyscrapers in this area north of Theater District.

The building site was originally planned for the use of the next-door neighbour Federal Reserve Bank's extension, but this privately developed office building eventually occupied the plot -- albeit also the bank eventually leased space from the building.

The building draws its inspiration from medieval castle design, with the multiple round towers which extend to the ground, as well as the holed balustrade at the building top, impersonating a battlement.

The regular row of windows running through the whole building brings the design inevitably to the late 20th century, with the resulting air of lightness and transparency.

As well as the circular pillars, also a set of narrower columns in-between define the building on the street level. They support a high arcade, behind which is the glass-walled lobby.

The 143 m tall building consists of four oval-shaped cylinders placed above each other, each smaller in diameter than the one below, creating the building a set-back appearance. On the 36-storey facade, red granite spandrels alternate with the shiny steel of horizontal window bands.

The elliptical lobby has a colonnade of steel-banded and "hat-topped" round pillars along the glassed outer wall line, and the columns double on the outside, forming a narrow arcade there.

Due to the placement of the elevators to the side away from Lexington Avenue, the "cylinders" are offset to the mid-block. One result of the unusual form of the building was the required installation of customized HVAC and ventilation fixtures, with the appropriate cost effects.

The building features 54,200 m² of office and 740 m² of retail space.

The brick-clad, 52-storey slab faces east and west, straddling its mid-block site between 59th and 60th Streets. The set-back top at 157.5 m creates double terraces facing south.

The building incorporates 498 rental apartments as well as a health club and 9,300 m² of medical offices for the nearby Roosevelt Hospital, with a separate entrance with ziggurat themes from 59th Street. The carage has space for 125 cars.

The site was originally owned by the Federal Government and contained the U.S. Assay Building (arch. James A. Wetmore, 1930). As the New York Assay Office, which had operated since 1853, was closed down in 1982, the plot was sold for $27 million.

The new development utilized the air rights from a demolished fire station (which is now located within the building, on the South Street side) and the neo-Renaissance 100 Old Slip, a former police station and the home of the NY Police Museum next door to the south.

The base of the building features a rectangular-in-plan, neo-Classical granite colonnade enclosing a 12 m high outside arcade with rectangular clerestory openings at the top. The base material and texture is a nod towards the landmarked Police Museum building.

Above the gray granite-clad base, the 37-storey building forms a tower plan of granite-clad, strip-windowed rectangle with corners of chamfered, dark-tinted glass curtain wall. This basic form then gradually transforms in a series of jagged steps and set-backs to a fully glass-walled octagon reaching 175.5 m.

Entrance to the building is from three of the corners (the fourth is for basement parking entrance), underneath the diagonal curtain wall portions, but set-back from the wall line so that the building corner columns extend through the atrium space (image). The colonnades and openings are echoed in the lobby outer walls, albeit naturally glazed. The lobby is of the same height as the atrium and has brown marble decor, floor paving in light tone and elevator bank walls in darker tones.

In plan, the office floors feature 16 corners in every configuration to the last granite-clad set-back. In all, the building incorporates 101,300 m² of office space, including a trading floor. 26 elevators serve the floors.

There is a public plaza along Gouverneur Lane, clad in the same red paving stones as the arcade and sidewalks.

Paramount Group purchased the building for $135 million in 1995.

The building consists of two masses as a generally L-shaped entity. Facing the plaza at the corner of Lexington Avenue and 57th Street, the 32-storey curving facade of the tower rises all the way to the top at 131 m. The corners of its top portion are chamfered, starting from the roof level of the adjoining lower wing to the west, in turn topped by an arched feature, housing what might be a solar panel installation. Both masses are set back from the base which has horizontally accentuated stone facing on the first two floors. The neo-Classical facades are clad in gray granite and feature unbroken vertical window stripes.

The building incorporates 42,900 m² of office and retail space. As the building was constructed from the beginning as an antiques center, the retail space design caters to these special needs; the walls and floors were specially protected against any dampness that might be seeping through and double doors are used to minimize humidity from the outside.

In 1997, Cohen Brothers obtained the building for $113 million and made a renovation that was completed in September 2001.

The plaza in front of the curving main facade is elevated from the street level and features a round granite "temple" flanked with fountains as its sculptural piece (image).

The Cohen Park, named after the owners, is a vest-pocket plaza next to the entrance to the Galleria next door. The park is enclosed within a two-floor-high extension of the street facade and features a 4.5-meter illuminated waterfall and landscaping by Thomas Balsley as well as sculptures by Franco Scuderi.

Originally, there had been plans for a joint high-rise development combining also the plot of the Carnegie Hall Tower. The plan came to nothing as the owner of the Russian Tea Room, which is located between the plots and extends through the block, refused to sell her property. Eventually both towers were built independently on their separate plots, only the 6-meter width of the restaurant's site separating them in the skies.

Clad in a dark glass curtain wall and rising from a rectangular base in scale with the surrounding buildings on 57th Street, the 68-storey tower differs strikingly in appearance from its rectangular, contextual colour brick neighbour. The tower has a triangular plan with the diagonal side facing north-east, towards Central Park. With only a notch at the top of the north edge and the jagged south edge breaking the prism form, the tower rises to the height of 218 m.

The building houses offices in the lower floors with 234 apartments on 49 floors occupying the upper portion of the tower. The residential portion features a private restaurant with outdoor terrace as well as a health club with a swimming pool.

The 56th street wall is set back from the plot line, forming a plaza with large brick planters. The lobby extends through the block; the ground floor has 280 m² of retail space and there is a basement garage.

L&L Acquisitions and Principal Life Insurance Co. bought the 22,800 m² office portion of the building for $120 million in June 2005.

The building replaced the cross-topped Seamen's Church Institute hostel only 16 years after its completion.

The plan of the building is in the shape of a quarter of a circle and the most striking portion of the facade, the curving wall of bluish glass, faces south, distinguishably different from the 1970s buildings that have so far dominated the immediate surroundings of the South Ferry.

The structural system of the building is visible at the ground floor level, where the perimeter columns support the uplifted facade, and the diagonally-braced center core and elevator shafts are visible behind glass curtain. (image).

A floor up, the building's main lobby has walls of glass as well as cobblestone paving.

Nesting beside the skyscrapers, the historic, colonnaded building at 7-8 Broad Street is the only remaining 18th Century private house in Downtown Manhattan.

The 56-storey building "duels" about the dominance of Columbus Circle airspace with the ex-Gulf and Western Building, facing it across the traffic circle. Until the completion of the planned New Coliseum project to replace the neighbouring New York Coliseum west of the Circle, these towers will continue to dominate the immediate surroundings.

The alumium-clad building is characterized by numerous setbacks and angled protrusions -- which offer views to three directions -- the rise ending to an octagonal water tank housing at 191.5 m. The building has a total of 160 apartments, as well as a health club and a roof-top sundeck.