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World Trade Center
The World Trade Center's Twin Towers
General information
Status	Destroyed on September 11, 2001
Location	New York City, NY, U.S.
Owner	Port Authority of New York and New Jersey
Height
Antenna spire	1,727 ft (526.3 m)
Roof	1,368 ft (417.0 m)
Top floor	1,355 ft (413.0 m)
Technical details
Floor area	8.6 million sq ft 800,000 m² (1 & 2)
Lifts/elevators	198 (1 & 2)
Design and construction
Architect(s)	Minoru Yamasaki, Emery Roth & Sons
Engineer	Leslie Robertson, Leslie E. Robertson Associates

The World Trade Center in New York City, United States (sometimes informally the WTC or Twin Towers) was a complex of seven buildings in Lower Manhattan that were attacked by Al-Qaeda on September 11, 2001. It was mostly designed by Detroit-based architect Minoru Yamasaki and engineer Leslie Robertson and developed by the Port Authority of New York and New Jersey. It was initiated in 1960 by a Lower Manhattan Association created and chaired by David Rockefeller, who had the original idea of building the center, with strong backing from the then-New York governor, his brother Nelson Rockefeller. The World Trade Center, New York, like most World Trade Centers located around the globe, belonged to the family of World Trade Centers Association. Prior to its destruction, Larry Silverstein held the most recent lease to the complex, the Port Authority having leased it to him in July 2001. The complex, located in the heart of New York City's downtown financial district, contained 13.4 million square feet (1.24 million m²) of office space, almost four percent of Manhattan's entire office inventory at that time.

Best known for its iconic 110-story twin towers (101 usable floors, eight engineering-only "service" floors on top of a lobby which was six stories high and 80') the World Trade Center was beset by a fire on February 13, 1975 and a bombing on February 26, 1993.

All seven original buildings in the complex were destroyed during the September 11 attacks. Three of the buildings collapsed: One World Trade Center (1 WTC, the North Tower), Two World Trade Center (2 WTC, the South Tower), and 7 World Trade Center (7 WTC). The Marriott World Trade Center (3 WTC) was crushed by the collapses of 1 WTC and 2 WTC. 4 World Trade Center (4 WTC), 5 World Trade Center (5 WTC), and 6 World Trade Center (6 WTC) were damaged beyond repair and later demolished. Three buildings not part of the complex were also destroyed: St. Nicholas Greek Orthodox Church was destroyed by the collapse of 2 WTC. The Deutsche Bank Building was damaged beyond repair by the explosions and collapse of 1 and 2 WTC; and Borough of Manhattan Community College's Fiterman Hall was damaged beyond repair by the collapse of 7 WTC; these are currently being deconstructed.

Planning and construction

The idea of establishing a "world trade center" in New York City was first proposed in 1946, with a bill passed by the New York State Legislature that allowed New York Governor Thomas E. Dewey to begin developing plans for the project. In 1949, plans for a "world trade center" were put on hold. In the late 1940s and 1950s, economic growth in New York City was concentrated in Midtown Manhattan, with Lower Manhattan left out. To help stimulate urban renewal, David Rockefeller suggested that the Port Authority should build a "world trade center" in Lower Manhattan.

Initial plans, made public in 1961, identified a site along the East River for the World Trade Center. The Port Authority, as a bi-state agency, required approval from both the governors of New York and New Jersey in order to undertake new proects. New Jersey Governor Robert B. Meyner objected to the plan, resenting that New York would be getting this $335 million project. Toward the end of 1961, negotiations with outgoing New Jersey Governor Meyner regarding the World Trade Center project reached a stalemate.

Meanwhile, ridership on New Jersey's Hudson and Manhattan Railroad (H&M) had declined substantially from a high of 113 million riders in 1927 to 26 million in 1958, after new automobile tunnels and bridges opened across the Hudson River. In a December 1961 meeting between Tobin and newly elected New Jersey Governor Richard J. Hughes, the Port Authority offered to take over the Hudson & Manhattan Railroad, which was renamed the Port Authority Trans-Hudson (PATH). The Port Authority also decided to move the World Trade Center project to the Hudson Terminal building site, on the west side of Lower Manhattan, which was a more convenient location for New Jersey commuters, who could get to the World Trade Center via PATH. The new location, along with Port Authority acquisition of the H&M Railroad, brought New Jersey to agreement on January 22, 1962, in support of the World Trade Center project.

Approval was also needed from New York City Mayor John Lindsay and the New York City Council, with disagreements centering on tax issues. A final agreement was made on August 3, 1966, that the Port Authority would make annual payments to the City, in lieu of taxes, for the portion of the World Trade Center leased to private tenants. In subsequent years, the payments would rise as the real estate tax rate increased.

Architectural design

On September 20, 1962, the Port Authority announced the selection of Minoru Yamasaki as lead architect, and Emery Roth & Sons as associate architects. Yamasaki devised the plan to incorporate twin towers, though Yamasaki's original plan called for the towers to be only 80 stories tall. In order to meet the Port Authority's requirement to build 10 million square feet (930,000 m²) of office space, the buildings would each need to be 110 stories tall.

A major limiting factor in building heights is elevators; the taller the building, the more elevators are needed to service the building, requiring more space-consuming elevator banks. Yamasaki and the engineers decided to use a new system with sky lobbies, which are floors where people can switch from a large-capacity express elevator, which goes only to the sky lobbies, to a local elevator that goes to each floor in a section (the local elevators can be stacked within the same elevator shaft). Located on the 44th and 78th floors of each tower, the sky lobbies enabled the elevators to be used efficiently, while also increasing the amount of usable space on each floor from 62 to 75 percent by reducing the number of required elevator shafts.. Altogether, the World Trade Center had 95 express and local elevators. This system was inspired by the New York City Subway system, whose lines include local stations where local trains stop and express stations where all trains stop.

Yamasaki's design for the World Trade Center, which was unveiled to the public on January 18, 1964, called for a square plan, approximately 207 feet (63 m) in dimension on each side. The buildings were designed with narrow office windows, only 18 inches (45 cm) wide, which reflected on Yamasaki's fear of heights and desire to make building occupants feel secure. Yamasaki's design included building facades sheathed in aluminum-alloy. The World Trade Center was one of the most striking American implementations of the architectural ethic of Le Corbusier, as well as the seminal expression of Yamasaki's gothic modernist tendencies. In addition to the twin towers, the plan for the World Trade Center complex included four other low-rise buildings; Altogether, the World Trade Center complex occupied a 16 acres (65,000 m) superblock.

Structural design

The structural engineering firm Worthington, Skilling, Helle & Jackson worked to implement Yamasaki's design, developing the tube-frame structural system used in the buildings. The Port Authority's Engineering Department served as foundation engineers, Joseph R. Loring & Associates as electrical engineers, and Jaros, Baum & Bolles as mechanical engineers. Tishman Realty & Construction Company was the general contractor on the World Trade Center project. Guy F. Tozzoli, director of the World Trade Department at the Port Authority, and the Port Authority's Chief Engineer, Rino M. Monti, oversaw the project. As an interstate agency, the Port Authority was not subject to local laws and regulations of the City of New York, including building codes. Nonetheless, the structural engineers of the World Trade Center ended up following draft versions of the new 1968 building codes.

The tube-frame design of the World Trade Center towers was a new approach, which allowed open floor plans, rather than columns distributed throughout the interior to support building loads as had traditionally been done. The World Trade Center towers utilized high-strength, load-bearing perimeter steel columns called Vierendeel trusses that were spaced closely together to form a strong, rigid wall structure, which supported virtually all lateral loads, such as wind loads, and shared the gravity loads with the core columns. The perimeter structure, which contained 59 perimeter columns, narrowly spaced, on each side of the buildings, was constructed with extensive use of prefabricated modular pieces, which consisted of three columns, three stories tall, connected by spandrel plates. The spandrel plates were welded to the columns to create the modular pieces off-site at the fabrication shop. Adjacent modules were bolted together, with the splices occurring at mid-span of the columns and spandrels. The spandrel plates were located at each floor, transmitting shear stress between columns, allowing them to work together in resisting lateral loads. The joints between modules were staggered vertically, so the column splices between adjacent modules were not at the same floor.

The building's core housed the elevator and utility shafts, restrooms, three stairwells, and other support spaces. The core of each tower was a rectangular area 87 by 135 feet (27 by 41 m), and contained 47 steel columns running from the bedrock to the top of the tower. The large, column-free space between the perimeter and core was bridged by prefabricated floor trusses. The floors supported their own weight, as well as live loads, provided lateral stability to the exterior walls, and distributed wind loads among the exterior walls. The floors consisted of 4 inch (10 cm) thick lightweight concrete slabs laid on a fluted steel deck. A grid of lightweight bridging trusses and main trusses supported the floors. The trusses connected to the perimeter at alternate columns, and were on 6 foot 8 inch (2.03 m) centers. The top chords of the trusses were bolted to seats welded to the spandrels on the exterior side and a channel welded to the core columns on the interior side. The floors were connected to the perimeter spandrel plates with viscoelastic dampers, which helped reduce the amount of sway felt by building occupants. The trusses supported a 4-inch (100 mm) thick (10 cm) lightweight concrete floor slab, with shear connections for composite action.

Hat trusses (or "outrigger truss") located from the 107th floor to the top of the buildings were designed to support a tall communication antenna on top of each building. Only 1 WTC (north tower) actually had an antenna fitted, which was added in 1978. The truss system consisted of six trusses along the long axis of the core and four along the short axis. This truss system allowed some load redistribution between the perimeter and core columns and supported the transmission tower.

The tube frame design using steel core and perimeter columns protected with sprayed-on fire resistant material created a relatively lightweight structure that would sway more in response to the wind, compared to traditional structures such as the Empire State Building that have thick, heavy masonry for fireproofing of steel structural elements. During the design process, wind tunnel tests were done to establish design wind pressures that the World Trade Center towers could be subjected to and structural response to those forces. Experiments also were done to evaluate how much sway occupants could comfortably tolerate, however many subjects experienced dizziness and other ill effects. One of the chief engineers Leslie Robertson worked with Canadian engineer Alan G. Davenport to develop viscoelastic dampers to absorb some of the sway. These viscoelastic dampers, used throughout the structures at the joints between floor trusses and perimeter columns, along with some other structural modifications reduced the building sway to an acceptable level.

Construction

In March 1965, the Port Authority began acquiring property at the World Trade Center site. Demolition work began on March 21, 1966 to clear thirteen square blocks of low rise buildings in Radio Row for construction of the World Trade Center. Groundbreaking for the construction of the World Trade Center took place on August 5, 1966.

The site of the World Trade Center was located on landfill, with the bedrock located 65 feet (20 m) below. In order to construct the World Trade Center, it was necessary to build the "bathtub", with a slurry wall along the West Street side of the site, which serves the purpose of keeping water from the Hudson River out. The slurry method, devised by Port Authority’s chief engineer, John M. Kyle, Jr., involved digging a trench, and as excavation proceeded, filling the space with a "slurry" mixture, composed of bentonite, which plugged holes and kept water out. When the trench was dug out, a steel cage was inserted, with concrete poured in, forcing the "slurry" out. It took fourteen months for the slurry wall to be completed, which was necessary before excavation of material from the interior of the site could begin. The 1.2 million cubic yards (917,000 m³) of material excavated were used to expand the Manhattan shoreline across West Street, creating Battery Park City.

In January 1967, the Port Authority awarded $74 million in contracts to various steel suppliers, and Karl Koch was hired to erect the steel. Tishman Realty & Construction was hired in February 1967 to oversee construction of the project. Construction work began on the North Tower in August 1968, while construction South Tower was underway in January 1969. The original Hudson Tubes, which carried PATH trains into Hudson Terminal, remained in service as elevated tunnels during the construction process until 1971, when a new PATH station opened. Nearby New York City Subway tubes also needed protection during construction, so that service was not interrupted.

The topping out ceremony of 1 WTC (North Tower) took place on December 23, 1970, while 2 WTC's ceremony (South Tower) occurred later on July 19, 1971. The first tenants moved into the North Tower in December 1970, and into the South Tower in January 1972. When the World Trade Center twin towers were completed, the total costs to the Port Authority had reached $900 million. The ribbon cutting ceremony was on April 4, 1973.

Criticism

Plans to build the World Trade Center were not without controversy. The site for the World Trade Center was the location of Radio Row, which was home to hundreds of commercial and industrial tenants, property owners, small businesses, and approximately 100 residents, many of whom fiercely resisted forced relocation. A group of small businesses affected filed injunction, challenging the Port Authority's power of eminent domain. The case made its way through the court system, reaching the United States Supreme Court, which refused to accept the case.

Private real estate developers and members of the Real Estate Board of New York, led by Empire State Building owner Lawrence A. Wien, also expressed concerns about this much "subsidized" office space going on the open market, competing with the private sector when there was already a glut of vacancies. Others questioned whether the Port Authority really ought to take on the project, which was described by some as a "mistaken social priority." Initially conceived (as the name suggests) as a complex dedicated to companies and organizations directly taking part in "world trade," they at first failed to attract the expected clientèle. During the early years, various governmental organizations became key tenants of the World Trade Center, including the State of New York. It was not until the 1980s that the city's perilous financial state eased, after which an increasing number of private companies — mostly financial firms tied to Wall Street — became tenants.

The World Trade Center design brought criticism of its aesthetics from the American Institute of Architects and other groups. Lewis Mumford, author of The City in History and other works on urban planning, criticized the project and described it and other new skyscrapers as "just glass-and-metal filing cabinets." The twin towers' narrow office windows, only 18 inches (460 mm) wide, were also disliked by many for impairing the view from the buildings.

The trade center's "superblock", which replaced a more traditional, dense neighborhood, was regarded by some critics as an inhospitable environment that disrupted the complicated traffic network typical of Manhattan. For example, in his book The Pentagon of Power, the technical historian Lewis Mumford denounced the center as an "example of the purposeless giantism and technological exhibitionism that are now eviscerating the living tissue of every great city." On the other hand, Mr. Yamasaki saw the expanse as a focal point of serenity amidst the chaos of the city.

For many years, the immense Austin J. Tobin Plaza was unwelcoming, and often beset by brisk winds at the ground level. In 1999, the outdoor plaza reopened after undergoing $12 million renovations, which involved replacing marble pavers with gray and pink granite stones, adding new benches, planters, new restaurants and food kiosks, and outdoor dining areas. In later years, the plaza became a center for outdoor concerts and other activities.

The complex

The Twin Towers

With construction of 7 World Trade Center in the 1980s, the World Trade Center had a total of seven buildings, but the most notable were the main twin towers which were each 110 stories tall. 1 WTC (the North Tower, which featured a 360-foot (110 m) high TV and radio antenna added in 1978, stood 1,368 feet (417 m) high, and 2 WTC (the South Tower, which contained the observation deck, was 1,362 feet (415 m) high. The length and breadth of the towers were 208 feet (63.4 m) x 208 feet (63.4 m). Although only Tower 1 featured an antenna, both buildings were designed to carry a broadcast mast. The basement concourse of the World Trade Center included The Mall at the World Trade Center, along with a PATH station.

When completed in 1972, 1 WTC became the tallest building on Earth, unseating the Empire State Building after a 40-year reign. 2 WTC became the second tallest building in the world when completed in 1973. 2 WTC did not need these facilities, so it remained 1,362 feet (415 m). Regardless, the WTC towers held the height record only briefly. As the building neared completion in 1973, work had already begun on Chicago's Sears Tower, which ultimately reached 1,450 feet (442 m). During a press conference in 1973, Minoru Yamasaki was asked, "Why two 110-story buildings? Why not one 220-story building?" His response was: "I didn't want to lose the human scale". With the World Trade Center's destruction, the Empire State Building again became the tallest building in New York, after spending almost 30 years as the third-tallest in the city.

Of the 110 stories, eight were set aside for technical services (mechanical floors) Level B6/B5, Floors 7/8, 41/42, 75/76 and 108/109, in four two-floor areas evenly spread up the building. All the remaining floors were free for open-plan offices. Each floor of the towers had 40,000 square feet (3,700 m) of space for occupancy. Each tower had 3.8 million square feet (350,000 m²) of office space. Altogether the entire complex of seven buildings had 11.2 million square feet (1.04 km²) of space.

During the 1990s, approximately 500 companies had offices in the complex, including many financial companies such as Morgan Stanley, Aon Corporation, Salomon Brothers, as well as the Port Authority itself. Electrical service to the towers was supplied by Consolidated Edison (ConEd) at 13,800 volts. This service passed through the World Trade Center Primary Distribution Center (PDC) and sent up through the core of the building to electrical substations located on the mechanical floors. The substations "stepped" the 13,800 primary voltage down to 480/277 volt secondary power and further to 120/208 volt general power and lighting service. The complex also was served by emergency generators located in the sublevels of the towers and on the roof of 5 WTC.

The 110th Floor of 1 WTC (North Tower) housed commercial and public service radio & television transmission equipment. The roof of 1 WTC contained a vast array of transmission antennas, including the 360 ft (approx 110m) center antenna mast, which was rebuilt in 1999 by Dielectric Inc. to accommodate DTV. The center mast contained the television signals for almost all NYC television broadcasters: WCBS-TV 2, WNBC-TV 4, WNYW 5, WABC-TV 7, WWOR-TV 9 Secaucus, WPIX 11, WNET 13 Newark, WPXN-TV 31, and WNJU 47. It also had four NYC FM broadcasters on it as well: WPAT-FM 93.1, WNYC 93.9, WKCR 89.9, and WKTU 103.5. Access to the roof was controlled from the WTC Operations Control Center (OCC) located in the B1 level of 2 WTC.

Observation deck and Windows on the World

Although most of the space in the WTC complex was off-limits to the public, 2 WTC (South Tower) featured a public observation area named "Top Of The World." When visiting the observation deck, visitors would first pass through security checks added after the 1993 World Trade Center bombing. Next, visitors were whisked to the 107th floor indoor observatory at a height of 1,310 feet (399 m) and greeted with a 360-degree view of the New York City skyline, and exhibitions including a three-dimensional scale model of Manhattan, and a simulated helicopter ride around the city. Weather permitting, visitors could take two short escalator rides up from the 107th floor and visit what was the world's highest outdoor viewing platform. At a height of 1,377 feet (420 m), visitors were able to take in a view of the North Tower and New York City unlike any other. On a clear day, visitors could see up to 49 miles (78 km) in any given direction. An anti-suicide fence was placed on the roof itself, with the viewing platform set back and elevated above it, requiring only an ordinary railing and leaving the view unobstructed, unlike the observation deck of the Empire State Building.

The North Tower (1 WTC) had a restaurant on the 107th floor called Windows on the World, which was an elegant restaurant known as a place for big celebrations, such as weddings. Windows on the World, which was developed by Joe Baum at a cost of more than $17 million, opened in April 1976. Aside from the main restaurant, two offshoots were also originally located at the top of the North Tower: "Hors d'Oeuvrerie" (offered a Danish smorgasbord during the day and sushi in the evening) and "Cellar in the Sky" (a small wine bar). Windows on the World also had a wine school program, run by Kevin Zraly. Windows on the World was closed for a period of time following the 1993 World Trade Center bombing, reopening in 1996. Hors d'Oeuvrerie and Cellar in the Sky were replaced with the "Greatest Bar on Earth" and "Wild Blue". In its last full year of operation, 2000, Windows on the World reported revenues of $37 million, making it the highest-grossing restaurant in the United States.

The other buildings

Five smaller buildings stood around the 16-acre (65,000 m²) block. One was the 22-floor hotel which opened in 1981 as the Vista Hotel and in 1995 became the Marriott World Trade Center (3 WTC) at the southwest corner of the site. Three low-rise buildings (4 WTC, 5 WTC, and 6 WTC) in the same hollow tube design as the towers also stood around the plaza. 6 World Trade Center, at the northwest corner, housed the United States Customs Service and the U.S. Commodities Exchange. 5 World Trade Center was located at the northeast corner, above the PATH station, and 4 World Trade Center was at the southeast corner. In 1987, a 47-floor office building called 7 WTC was built north of the block. Beneath the World Trade Center complex was an underground shopping mall, which in turn had connections to various mass transit facilities, including the New York City Subway system and the Port Authority's own PATH trains connecting Manhattan to Jersey City, Hoboken, and Newark.

One of the world's largest gold depositories was stored underneath the World Trade Center, owned by a group of commercial banks. The 1993 bomb detonated close to the vault, but it withstood the explosion, as did the towers. Seven weeks after the September 11 attacks, $230 million in precious metals were removed from basement vaults of 4 WTC, which included 3,800 100-Troy-ounce registered gold bars and 30,000 1,000-ounce silver bars.

Life and events

On a typical weekday 50,000 people worked in the towers, with another 200,000 passing through as visitors. The complex was so large that it had its own zip code, 10048. The towers offered spectacular views from the observation deck (located on top of the South Tower) and the Windows on the World restaurant (located on top of the North Tower). The Twin Towers became known worldwide, appearing in movies, TV shows, postcards, merchandise, magazines and much more, and became a New York icon, in the same league as the Empire State Building and Statue of Liberty. French high wire acrobatic performer Philippe Petit walked between the towers on a tightrope in 1974, Brooklyn toymaker George Willig scaled the south tower in 1977, and high-rise firefighting/rescue advocate Dan Goodwin climbed the North Tower in 1983.

The 1995 PCA world chess championship, between Garry Kasparov and Viswanathan Anand, was played on the 107th floor of the South Tower. In January 1998, Ralph Guarino collected three men, Melvin, Richie, and Mike Reed to steal up towards 2.8 Million dollars from One World Brink bank on the eleventh floor of the World Trade Center. The heist was completed, however only 1.6 Million was stolen, mostly in Italian lira, francs, and yen. Subsequently all four were arrested; Ralph became an informant for the FBI against the DeCavalcante crime family which operated out of New Jersey.

February 13, 1975 fire

On February 13, 1975, a three-alarm fire broke out on the 11th floor of the North Tower, with fire spreading through the core from the 9th to 14th floors where electrical wiring was damaged. The fire ignited the insulation of telephone cables in a utility shaft that ran vertically between floors. The fire spread to other floors through openings in the floor slabs that were used to carry phone wires. The fires on other floors were extinguished almost immediately, and the main fire was put out in a few hours. Most of the damage was concentrated on the 11th floor, with the fire fueled by cabinets filled with paper, alcohol-based fluid for office machines, and other office equipment. Fireproofing protected the steel from melting and there was no structural damage to the tower. Other than the damage caused by the fire, a few floors below suffered water damage from the extinguishing of the fires above. At that time, the World Trade Center was not equipped with sprinkler systems.

Bombing of February 26, 1993

On February 26, 1993 at 12:17 PM, a Ryder truck filled with 1,500 pounds (680 kg) of explosives was planted by Ramzi Yousef and detonated in the underground garage of the North Tower, opening a 100 foot (30 m) hole through 5 sublevels of concrete leaving six people dead and 50,000 other workers and visitors gasping for air in the shafts of the 110 story towers.

Many people inside the North Tower were forced to walk down darkened stairwells that contained no emergency lighting, some taking two hours or more to reach safety. As the Port Authority was a bistate agency, the towers were exempt from New York City building codes. Subsequent to the bombing The Port Authority installed emergency lighting in the stairwells. It is believed that this lighting saved many lives during the events of September 11, 2001.

In 1997 and 1998, six Islamist extremists were convicted and sentenced to life in prison for their roles in the bombing. According to a presiding judge, the conspirators' chief aim at the time of the attack was to destabilize the north tower and send it crashing into the south tower, toppling both landmarks.

As a memorial to the victims of the bombing of the tower, a reflecting pool was installed with the names of those who had been killed in the blast. Following the September 11, 2001 attacks, relief workers found a single fractured piece of the fountain etched with the word "John"; to date it is the only remaining part of the 1993 memorial that survived the collapse of the towers.

The World Trade Center complex was protected by an extensive fire detection and voice evacuation paging system upgraded after the 1993 bombing. Fire Command Stations, staffed by Fire Safety Directors were located in the lobbies of each building and the Operations Control Center (OCC) monitored these systems. An extensive study of the performance of World Trade Center Fire Protection Systems was conducted by the National Institute of Standards and Technology (NIST) following 2001-09-11.

Lease

In 1998, plans were approved by the Port Authority to privatize the World Trade Center. In 2001, the Port Authority sought to lease the World Trade Center to a private entity. Bids for the lease came from Vornado Realty Trust, a joint bid between Brookfield Properties Corporation and Boston Properties, and a joint bid by Silverstein Properties and The Westfield Group. By privatizing the World Trade Center, it would be added to the city's tax rolls. The lease was also intended to raise funds for other Port Authority projects. On February 15, 2001, the Port Authority announced that Vornado Trust Realty had won the lease for the World Trade Center, paying $3.25 billion for the 99-year lease. Vornado Realty outbid Silverstein by $600 million, though Silverstein upped his offer to $3.22 billion. However, Vornado insisted on last minute changes to the deal, including a shorter 39-year lease, which the Port Authority considered nonnegotiable. Vornado later withdrew and Silverstein's bid for the lease to the World Trade Center was accepted on April 26, 2001, and closed on July 24, 2001.

September 11, 2001

On September 11, 2001 at 8:46 a.m. Eastern Time, Al Qaeda suicide hijackers crashed American Airlines Flight 11 into the northern facade of the North Tower. Seventeen minutes later, at 9:03 a.m., a second team of hijackers crashed United Airlines Flight 175 into the South Tower, which subsequently collapsed at 9:59 a.m. The damage caused to the North Tower by Flight 11 destroyed any means of escape from above the impact zone, trapping 1,344 people. The North Tower collapsed at 10:28, after burning for approximately 102 minutes.

At 5:20 p.m. on September 11, 2001, 7 World Trade Center collapsed due to uncontrolled fires causing structural failure. 3 World Trade Center, a Mariott hotel, was destroyed during the collapse of the two towers. The three remaining buildings in the WTC plaza sustained heavy damage from debris, and were ultimately demolished. The Deutsche Bank Building across Liberty Street from the World Trade Center complex was later condemned due to the uninhabitable, toxic conditions inside the office tower, and is undergoing deconstruction. The Borough of Manhattan Community College's Fiterman Hall at 30 West Broadway was also condemned due to extensive damage in the attacks, and is slated for deconstruction.

At the time of the incident, media reports suggested that tens of thousands might have been killed in the attacks, as on any given day upwards of 50,000 people could be inside the towers. Ultimately, 2,749 death certificates were filed relating to the 9/11 attacks. Of these, 1,614 (59%) were identified from recovered physical remains. Cantor Fitzgerald L.P., an investment bank on the 101st–105th floors of One World Trade Center, lost 658 employees, considerably more than any other employer. Marsh Inc., located immediately below Cantor Fitzgerald on floors 93–101 (the location of Flight 11's impact), lost 295 employees, and 175 employees of Aon Corporation were killed. As well, 343 deaths were New York City firefighters, 84 were Port Authority employees, of whom 37 were members of the Port Authority Police Department, and another 23 were New York City Police Department officers. Of all the people who were still in the towers when they collapsed only 20 of these people were pulled out alive.

Rebuilding

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The process of cleanup and recovery, which continued 24 hours a day and, at the World Trade Center site took eight months. Debris was transported from the World Trade Center site to Fresh Kills on Staten Island, where it was further sifted. On May 30, 2002, a ceremony was held to officially mark the end of the cleanup efforts. In 2002, ground was broken on construction of a new 7 World Trade Center building, located just to the north of the main World Trade Center site. Since it was not part of the site master plan, Larry Silverstein was able to proceed without delay on rebuilding of 7 World Trade Center. On May 23, 2006, 7 World Trade Center officially opened.

With the main World Trade Center site, numerous stakeholders were involved, including Silverstein, as well as the Port Authority which in turn meant that the Governor of New York State, George Pataki, also had some authority. As well, the victims' families, people in the surrounding neighborhoods, Mayor Michael Bloomberg and others wanted input. The Lower Manhattan Development Corporation was established to coordinate the reconstruction of the World Trade Center site. The LMDC held a competition to solicit possible designs for the site. Memory Foundations by Daniel Libeskind was selected as the master plan for the World Trade Center site. The plan included the 1,776-foot (541 m) Freedom Tower, as well as a memorial and a number of other office towers. Out of the World Trade Center Site Memorial Competition, a design by Michael Arad and Peter Walker, entitled Reflecting Absence, was selected in January 2004 for the World Trade Center Memorial.

On March 13, 2006, workers arrived at the World Trade Center site to remove remaining debris and start surveying work. This marks the official start of construction of the WTC Memorial and Museum. In April 2006, the owner of the site, The Port Authority, and private developer Larry Silverstein reached a tentative agreement. The main elements of that agreement are that Silverstein ceded rights to develop the Freedom Tower and Tower Five in exchange for financing with Liberty Bonds for Tower Two, Three, and Four, which are considered the most marketable properties of the site. On April 27, 2006, a ground-breaking ceremony was held for the Freedom Tower.

In May 2006, architects Richard Rogers and Fumihiko Maki were announced as the architects for Towers Three and Four, respectively. The final designs for Towers Two, Three and Four were unveiled on September 7, 2006. Tower Two, or 200 Greenwich Street, will have a roof height of 1,254 feet (382 m) and a 96-foot (29 m) tripod spire for a total of 1,350 feet (411 m). Tower Three, or 175 Greenwich Street will have a roof height of 1,155 feet (352 m) and an antennae height of 1,255 feet (383 m). Tower Four, or 150 Greenwich Street, will have an overall height of 946 feet (288 m). On June 22, 2007 the Port Authority of New York and New Jersey announced that JP Morgan Chase will build Tower 5, a 42-story building on Site 5 currently occupied by the Deutsche Bank Building. Kohn Pedersen Fox was officially chosen as the architect for the building on July 17, 2007.

Film and media

The World Trade Center was an iconic structure and has been featured in numerous films, as well as appearing in many television shows, cartoons, comic books, computer/video games and music videos. The events surrounding September 11 are portrayed in several documentaries and movies, including two major motion pictures made in 2006, Oliver Stone's World Trade Center and Paul Greengrass' United 93. Several movies released shortly after 9/11 digitally erased the Twin Towers from skyline shots, such as Spider-Man (film). As of 2007, most reruns of popular television shows have chosen to leave the Twin Towers in airings of the show such as cut scenes in Friends and episodes of The Simpsons. An exception to this is the opening intro to HBO's Sex and The City, which removed shots of the Towers as a mark of respect for the victims.

References

1. SkyscraperPage - One World Trade Center, source:Federal Communications Commission
2. The Height of Ambition, The New York Times September 8, 2002.
3. "Governor Pataki, Acting Governor DiFrancesco Laud Historic Port Authority Agreement To Privatize World Trade Center" (Press release). Port of New York and New Jersey. July 21, 2001.
4. Buildings.com. "Four Percent of Manhattan's Total Office Space Was Destroyed in the World Trade Center Attack".
5. "Dewey Picks Board for Trade Center". The New York Times. July 6, 1946.
6. "Lets Port Group Disband, State Senate for Dissolution of World Trade Corporation". The New York Times. March 11, 1949.
7. ^ Gillespie, Angus K. (1999). "Chapter 1". Twin Towers: The Life of New York City's World Trade Center. Rutgers University Press.
8. ^ Grutzner, Charles (December 29, 1961). "Port Unit Backs Linking of H&M and Other Lines". The New York Times.
9. Cudahy, Brian J. (2002). Rails Under the Mighty Hudson. Fordham University Press. pp. p. 56. {{cite book}}: |pages= has extra text (help)
10. Wright, George Cable (January 23, 1962). "2 States Agree on Hudson Tubes and Trade Center". The New York Times.
11. Smith, Terence (August 4, 1966). "City Ends Fight with Port Body on Trade Center". The New York Times.
12. Smith, Terence (January 26, 1967). "Mayor Signs Pact on Trade Center". The New York Times.
13. Esterow, Milton (September 21, 1962). "Architect Named for Trade Center". The New York Times.
14. ^ Huxtable, Ada Louise (January 19, 1964). "A New Era Heralded". The New York Times.
15. ^ Huxtable, Ada Louise (January 26, 1964). "Biggest Buildings Herald New Era". The New York Times.
16. Lew, H.S., Richard W. Bukowski, Nicholas J. Carino (September 2005). Design, Construction, and Maintenance of Structural and Life Safety Systems (NCSTAR 1-1). National Institute of Standards and Technology. pp. p. 9. {{cite book}}: |pages= has extra text (help)CS1 maint: multiple names: authors list (link)
17. Gillespie, Angus K. (1999). "Chapter 2". Twin Towers: The Life of New York City's World Trade Center. Rutgers University Press.
18. ^ Ruchelman, Leonard I. (1977). The World Trade Center: Politics and Policies of Skyscraper Development. Syracuse University Press. pp. p. 11. {{cite book}}: |pages= has extra text (help)
19. Gillespie, Angus K. (1999). Twin Towers: The Life of New York City's World Trade Center. Rutgers University Press. pp. p. 76. {{cite book}}: |pages= has extra text (help)
20. Lew, H.S., Richard W. Bukowski, Nicholas J. Carino (September 2005). Design, Construction, and Maintenance of Structural and Life Safety Systems (NCSTAR 1-1). National Institute of Standards and Technology. pp. p. 7. {{cite book}}: |pages= has extra text (help)CS1 maint: multiple names: authors list (link)
21. ^ Pekala, Nancy (2001-11-01). "Profile of a lost landmark; World Trade Center". Journal of Property Management. Cite error: The named reference "pekala" was defined multiple times with different content (see the help page).
22. ^ Huxtable, Ada Louise (May 29, 1966). "Who's Afraid of the Big Bad Buildings". The New York Times.
23. National Construction Safety Team (September 2005). "Chapter 1". Final Report on the Collapse of the World Trade Center Towers (PDF). NIST. pp. p. 1. {{cite book}}: |pages= has extra text (help)
24. Lew, H.S., Richard W. Bukowski, Nicholas J. Carino (September 2005). Design, Construction, and Maintenance of Structural and Life Safety Systems (NCSTAR 1-1). National Institute of Standards and Technology. pp. p. xxxviii. {{cite book}}: |pages= has extra text (help)CS1 maint: multiple names: authors list (link)
25. ^ "Final Report on the Collapse of the World Trade Center (chapter 1)" (PDF). National Institute of Standards and Technology (NIST). 2005. {{cite web}}: Unknown parameter |month= ignored (help)
26. National Construction Safety Team (September 2005). Final Report on the Collapse of the World Trade Center Towers (PDF). NIST. pp. p. 8. {{cite book}}: |pages= has extra text (help)
27. "New York: A Documentary Film - The Center of the World (Construction Footage)". Port Authority / PBS. Retrieved 2007-05-16.
28. Glanz, James and Eric Lipton (2003). City in the Sky. Times Books. pp. p. 138. {{cite book}}: |pages= has extra text (help)
29. Fanella, David A., Arnaldo T. Derecho, S.K. Ghosh (September 2005). Design and Construction of Structural Systems (NCSTAR 1-1A). National Institute of Standards and Technology. pp. p. 65. {{cite book}}: |pages= has extra text (help)CS1 maint: multiple names: authors list (link)
30. Glanz, James and Eric Lipton (2003). City in the Sky. Times Books. pp. p. 139-144. {{cite book}}: |pages= has extra text (help)
31. Glanz, James and Eric Lipton (2003). City in the Sky. Times Books. pp. p. 160-167. {{cite book}}: |pages= has extra text (help)
32. Ingraham, Joseph C. (March 29, 1965). "Port Agency Buys Downtown Tract". The New York Times.
33. Gillespie, Angus K. (1999). Twin Towers: The Life of New York City's World Trade Center. Rutgers University Press. pp. p. 61. {{cite book}}: |pages= has extra text (help)
34. Federal Emergency Management Agency (2002). "Chapter 1". World Trade Center Building Performance Study. {{cite book}}: Unknown parameter |month= ignored (help)
35. Iglauer, Edith (November 4, 1972). "The Biggest Foundation". The New Yorker.
36. Kapp, Martin S (July 9, 1964). "Tall Towers will Sit on Deep Foundations". Engineering News Record.
37. ^ Gillespie, Angus K. (1999). Twin Towers: The Life of New York City's World Trade Center. Rutgers University Press. pp. p. 68. {{cite book}}: |pages= has extra text (help)
38. Gillespie, Angus K. (1999). Twin Towers: The Life of New York City's World Trade Center. Rutgers University Press. pp. p. 71. {{cite book}}: |pages= has extra text (help)
39. "New York Gets $90 Million Worth of Land for Nothing". Engineering News Record. April 18, 1968.
40. "Contracts Totaling $74,079,000 Awarded for the Trade Center". The New York Times. January 24, 1967.
41. Kihss, Peter (February 27, 1967). "Trade Center Job To Go To Tishman". The New York Times.
42. ^ "Timeline: World Trade Center chronology". PBS - American Experience. Retrieved 2007-05-15.
43. Carroll, Maurice (December 30, 1968). "A Section of the Hudson Tubes is Turned into Elevated Tunnel". The New York Times.
44. Lew, H.S., Richard W. Bukowski, Nicholas J. Carino (September 2005). Design, Construction, and Maintenance of Structural and Life Safety Systems (NCSTAR 1-1). National Institute of Standards and Technology. pp. p. xxxvi. {{cite book}}: |pages= has extra text (help)CS1 maint: multiple names: authors list (link)
45. Cudahy, Brian J. (2002). "Chapter 3". Rails Under the Mighty Hudson: The Story of the Hudson Tubes, the Pennsy Tunnels, and Manhattan Transfer. Fordham University Press.
46. "World Trade Center - Minoru Yamasaki". Greatbuildings.com. Retrieved 2006-04-06.
47. Clark, Alfred E. (June 27, 1962). "Injunction Asked on Trade Center". The New York Times.
48. Arnold, Martin (November 13, 1963). "High Court Plea is Lost by Foes of Trade Center". The New York Times.
49. 375 US. 4 - Courtesy Sandwich Shop, Inc., et al. v. Port of New York Authority
50. Knowles, Clayton (February 14, 1964). "New Fight Begun on Trade Center". The New York Times.
51. "Kheel Urges Port Authority to Sell Trade Center". The New York Times. November 12, 1969.
52. Steese, Edward (March 10, 1964). "Marring City's Skyline". The New York Times.
53. Whitman, Alden (March 22, 1967). "Mumford Finds City Strangled By Excess of Cars and People". The New York Times.
54. Dunlap, David W (December 7, 2006). "At New Trade Center, Seeking Lively (but Secure) Streets". The New York Times. {{cite news}}: Italic or bold markup not allowed in: |publisher= (help)
55. "World Trade Center Plaza Reopens with Summer-long Performing Arts Festival". PANYNJ. June 9, 1999.
56. "World Trade Center, New York City". Emporis. Retrieved 2006-04-13.
57. "Sears Tower Building Information". Retrieved 2006-09-11.
58. "1973: World Trade Center Is Dynamic Duo of Height". Engineering News-Record. 1999-08-16. Archived from the original on 2002-06-11.
59. "World Trade Center Building Performance Study" (PDF). FEMA. Retrieved 2007-03-08. Six 1,200-kilowatt(kW) emergency power generators located in the sixth basement (B-6) level provided a secondary power supply.
60. Amy Florence Fischbach (January 1, 2001). "Towering security". CEE News. Retrieved 2007-03-08. E-J Electric set four generators on the roof of Tower 5, which was nine stories, as opposed to the 110-story Towers 1 and 2. E-J then ran high-voltage feeder cable to Towers 1, 2, 4 and 5, installed three substations and distributed power to the tenants.
61. Federal Communications Commission (FCC) Home Page
62. ^ Zraly, Kevin (2006). Windows on the World Complete Wine Course. Sterling Publishing Company. pp. p. 260. {{cite book}}: |pages= has extra text (help)
63. ^ Grimes, William (2001-09-19). "Windows That Rose So Close To the Sun". The New York Times.
64. Greenhouse, Steven (2002-06-04). "Windows on the World Workers Say Their Boss Didn't Do Enough". The New York Times.
65. Rediff.com – Buried WTC gold returns to futures trade
66. The Week in Chess 358, September 17 2001
67. "Trade Center Hit by 6-Floor Fire". The New York Times. 1975-02-14. Retrieved 2008-09-11. {{cite news}}: Italic or bold markup not allowed in: |publisher= (help)
68. "The Emergency Response Operations" (PDF). Federal Building and Fire Safety Investigation of the World Trade Center Disaster. NIST. 2005. Retrieved 2008-09-11. {{cite web}}: Unknown parameter |month= ignored (help)
69. Microsoft Word - NCSTAR 1-4C Fire Alarm.doc
70. Herman, Eric (February 6, 2001). "PA to ease WTC tax load, rent would be cut to offset hike by city". New York Daily News.
71. Bagli, Charles V. (January 31, 2001). "Bidding for Twin Towers". The New York Times. {{cite news}}: Italic or bold markup not allowed in: |publisher= (help)
72. ^ Cuozzo, Steve (January 30, 2001). "Larry Lusts for Twin Towers; Silverstein has an Eye on WTC's; Untapped Retail Potential". New York Post.
73. Herman, Eric (January 31, 2001). "Port Authority Gets Final Bids on WTC". New York Daily News.
74. "Brookfield Loses Lease Bid". Toronto Star. February 23, 2001.
75. Bagli, Charles V. (March 20, 2001). "As Trade Center Talks Stumble, No. 2 Bidder Gets Another Chance". The New York Times. {{cite news}}: Italic or bold markup not allowed in: |publisher= (help)
76. Bagli, Charles V. (April 27, 2001). "Deal Is Signed To Take Over Trade Center". The New York Times. {{cite news}}: Italic or bold markup not allowed in: |publisher= (help)
77. Smothers, Ronald (July 25, 2001). "Leasing of Trade Center May Help Transit Projects, Pataki Says". The New York Times. {{cite news}}: Italic or bold markup not allowed in: |publisher= (help)
78. "9/11 Commission Report". The National Commission on Terrorist Attacks Upon the United States.
79. Dwyer, Jim (2002-05-26). "102 Minutes: Last Words at the Trade Center; Fighting to Live as the Towers Die". The New York Times. Archived from the original on 2008-10-10. Retrieved 2008-05-23. {{cite news}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
80. Lawson, J. Randall, Robert L. Vettori (2005). "NIST NCSTAR 1-8 - The Emergency Response" (PDF). National Institute of Standards and Technology. pp. p. 37. {{cite web}}: |pages= has extra text (help); Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
81. "Final Report on the Collapse of World Trade Center Building 7 - Draft for Public Comment" (PDF). NIST. 2008. pp. xxxii. {{cite web}}: Unknown parameter |month= ignored (help)
82. "World Trade Center Building Performance Study". FEMA. 2002. Retrieved 2007-07-12. {{cite web}}: Unknown parameter |month= ignored (help)
83. "World Trade Center Building Performance Study - Bankers Trust Building" (PDF). FEMA. 2002. Retrieved 2007-07-12. {{cite web}}: Unknown parameter |month= ignored (help)
84. "The Deutsche Bank Building at 130 Liberty Street". Lower Manhattan Construction Command Center. Retrieved 2007-07-12.
85. "Lower Manhattan - Fiterman Hall". LowerManhattan.info. 2007-7. Retrieved 2007-07-10. {{cite web}}: Check date values in: |date= (help)
86. "NYC links first death to 9/11 toxic dust". Associated Press. May 23, 2007. Retrieved May 24. {{cite web}}: Check date values in: |accessdate= (help); Unknown parameter |accessyear= ignored (|access-date= suggested) (help)
87. "Cantor rebuilds after 9/11 losses". BBC. 2006-09-04. Retrieved 2008-05-20.
88. Siegel, Aaron (2007-09-11). "Industry honors fallen on 9/11 anniversary". InvestmentNews. Retrieved 2008-05-20.
89. "Ceremony closes 'Ground Zero' cleanup". CNN. 2002-05-30. Retrieved 2008-09-11.
90. Lower Manhattan Development Corp. "Selected Design for the WTC Site as of February 2003".
91. Westfeldt, Amy (March 13, 2006). "Construction Begins On World Trade Center Memorial". New York Sun.
92. Construction Begins at Ground Zero (AP story)
93. Designs Unveiled for Freedom Tower’s Neighbors
94. JP Morgan releases WTC tower plans
95. Kohn Responds to WTC5 Criticisms

External links

• World Trade Center official site
• National September 11 Memorial & Museum at the World Trade Center (official site)
• DMOZ directory

40°42′42″N 74°00′45″W / 40.71167°N 74.01250°W / 40.71167; -74.01250 af:Wêreldhandelsentrum am:ዓለም ንግድ ሕንጻ ar:مركز التجارة العالمي bn:ওয়ার্ল্ড ট্রেড সেন্টার bs:Svjetski trgovački centar bg:Световен търговски център (Ню Йорк) ca:Torres Bessones cs:World Trade Center cy:Canolfan Masnach y Byd da:World Trade Center de:World Trade Center el:Παγκόσμιο Κέντρο Εμπορίου es:World Trade Center eo:World Trade Center eu:Dorre Bikiak fa:مرکز تجارت جهانی fr:World Trade Center ko:세계 무역 센터 hr:Svjetski trgovački centar id:World Trade Center is:World Trade Center it:World Trade Center he:מגדלי התאומים ka:მსოფლიო სავაჭრო ცენტრი lb:World Trade Center lt:Pasaulio prekybos centras hu:Világkereskedelmi Központ ml:ലോക വ്യാപാര കേന്ദ്രം ms:World Trade Center nah:Ōme Huēyicnīuhcalli nl:World Trade Center (New York) ja:ワールドトレードセンター (ニューヨーク) no:Verdens Handelssenter i New York nn:Verdshandelssenteret i New York oc:World Trade Center pl:World Trade Center pt:World Trade Center ro:World Trade Center qu:Awacha turrikuna ru:Всемирный торговый центр (Нью-Йорк) sq:World Trade Center scn:World Trade Center simple:World Trade Center sk:Svetové obchodné centrum sr:Светски трговински центар sh:Svjetski Trgovački Centar fi:World Trade Center sv:World Trade Center ta:உலக வர்த்தக மையம் th:เวิลด์เทรดเซ็นเตอร์ vi:Trung tâm Thương mại Thế giới tr:Dünya Ticaret Merkezi (bina) uk:Всесвітній торговий центр ur:ورلڈ ٹریڈ سینٹر vls:WTC-toorns yi:World Trade Center zh:世界贸易中心

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