One World Trade Center
One World Trade Center (also known as One World Trade, One WTC, and formerly Freedom Tower) is the main building of the rebuilt World Trade Center complex in Lower Manhattan, New York City. One WTC is the tallest building in the United States, the tallest building in the Western Hemisphere, and the seventh-tallest in the world. The supertall structure has the same name as the North Tower of the original World Trade Center, which was destroyed in the terrorist attacks of September 11, 2001. The new skyscraper stands on the northwest corner of the World  Trade Center site, on the site of the original 6 World Trade Center. The building is bounded by West Street to the west, Vesey Street to the north, Fulton Street to the south, and Washington Street to the east. The building's architect is David Childs, whose firm Skidmore, Owings & Merrill (SOM) also designed the Burj Khalifa and the Willis Tower. The construction of below-ground utility relocations, footings, and foundations for the new building began on April 27, 2006. One World Trade Center became the tallest structure in New York City on April 30, 2012, when it surpassed the  height of the Empire State Building. The tower's steel structure was topped out on August 30, 2012. On May 10, 2013, the final component of the skyscraper's spire was installed, making the building, including its spire, reach a total height of . Its height in feet is a deliberate reference to the year when the United States Declaration of Independence was signed. The building opened on November 3, 2014; the One World Observatory opened on May 29, 2015. On March 26, 2009, the Port Authority of New York and New Jersey (PANYNJ) confirmed that the building would be officially  known by its legal name of "One World Trade Center", rather than its colloquial name of "Freedom Tower". The building has 94 stories, with the top floor numbered 104. The new World Trade Center complex will eventually include five high-rise office buildings built along Greenwich Street, as well as the National September 11 Memorial & Museum, located just south of One World Trade Center where the original Twin Towers stood. The construction of the new building is part of an effort to memorialize and rebuild following the destruction of the original World Trade Center complex. Original building (1971–2001). Construction. The  construction of the World Trade Center, of which the Twin Towers (One and Two World Trade Center) were the centerpieces, was conceived as an urban renewal project and spearheaded by David Rockefeller. The project was intended to help revitalize Lower Manhattan. The project was planned by the Port Authority of New York and New Jersey, which hired architect Minoru Yamasaki. He came up with the idea of building twin towers. After extensive negotiations, the New Jersey and New York State governments, which supervise the Port Authority, consented to the construction of the World Trade Center at the Radio Row site , located in the lower-west area of Manhattan. To satisfy the New Jersey government, the Port Authority agreed to buy the bankrupt Hudson & Manhattan Railroad (renamed to Port Authority Trans-Hudson), which transported commuters from New Jersey to Lower Manhattan. The towers were designed as framed tube structures, giving tenants open floor plans, unobstructed by columns or walls. The framed tube design was introduced by Bangladeshi-American structural engineer Fazlur Rahman Khan in the 1960s. The design was accomplished by using many closely spaced perimeter columns, providing much of the structure's strength, with the gravity load shared with the  core columns. The elevator system, which made use of sky lobbies and a system of express and local elevators, allowed substantial floor space to be used for office purposes by making the structural core smaller. The design and construction of the towers involved many other innovative techniques, such as wind tunnel experiments and the slurry wall for digging the foundation. Yamasaki also incorporated elements of Islamic architecture in the building's design, having previously designed Saudi Arabia's Dhahran International Airport with the Saudi Binladin Group. Construction of the North Tower (One World Trade Center) began in August 1966; extensive  use of prefabricated components sped up the construction process. The first tenants moved into the North Tower in October 1971. In the 1970s, four other low-level buildings were built as part of the World Trade Center complex. A seventh building was built in the mid-1980s. Specifications and operations. After Seven World Trade Center was built in the 1980s, the World Trade Center complex had a total of seven buildings; however, the most notable ones were the main Twin Towers built in the 1970s—One World Trade Center was the North Tower, and Two World Trade Center was the South  Tower. Each tower was over high, and occupied about of the total of the site's land. During a press conference in 1973, 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." When it was topped out in October 1971, One World Trade Center became the tallest building in the world, surpassing the Empire State Building, which had held the record for 40 years. The North Tower was tall, and in 1978, a telecommunications antenna was added to the top of the roof ; by itself, the antenna was tall. With the -tall antenna, the highest point of the North Tower reached . However, the tower only held its record until , when Chicago's Sears Tower (now Willis Tower), which was tall at the rooftop, was completed. At 110 floors, the World Trade Center towers had more floors than any other building at that time. This number was not surpassed until the construction of the Burj Khalifa (163 floors), which opened in 2010. Of the 110 stories, 8 were set aside as mechanical floors (floors 7/8, 41/42, 75/76, and 108/109), which were 4 two-floor  areas that were spaced up the building in even intervals. All the remaining floors were open for tenants. Each floor of the tower had of available space. The North and South tower had of total office space. The entire complex of seven buildings had a combined total of of office space. The complex initially failed to attract the expected clientele. During the early years, various governmental organizations became key tenants of the World Trade Center, such as the State of New York. In the 1980s, the city's perilous financial condition eased, after which an increasing number of private companies —mostly financial firms related to Wall Street—became tenants. During the 1990s, approximately 500 companies had offices in the complex, including financial companies such as Morgan Stanley, Aon Corporation, and Salomon Brothers. The basement concourse of the World Trade Center included The Mall at the World Trade Center, and a PATH station. The North Tower became the main corporate headquarters of Cantor Fitzgerald, and it also became the headquarters of the Port Authority of New York and New Jersey. The tower's electrical service was supplied by Consolidated Edison (ConEd) at 13,800 volts. The electricity passed through the World Trade  Center Primary Distribution Center (PDC), and was then sent up the building's core to electrical substations located on the mechanical floors. The substations lowered the 13,800 primary voltage to 480/277 volts, and the voltage was then further lowered to 208/120 volts for general power and lighting services. The complex was also served by emergency generators located in the sub-levels of the towers and on the roof of Five World Trade Center. The 110th floor of One World Trade Center (the North Tower) housed radio and television transmission equipment. The roof of the North Tower contained a vast array  of transmission antennas, including the center antenna mast, rebuilt by Dielectric Inc. to support DTV in 1999. 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 Linden. It also had four NYC FM broadcasters: WPAT-FM 93.1, WNYC 93.9, WKCR 89.9, and WKTU 103.5. Access to the roof was controlled by the WTC Operations Control Center (OCC), located in the B1 level of the South Tower. After the September 11  attacks of 2001, broadcasting equipment for the radio and television stations was installed at the Empire State Building. On a typical weekday, a combined total of 50,000 people worked in the North and South Towers, with another 140,000 passing through as visitors. The complex was so large that it had its own zip code: 10048. The Windows on the World restaurant, located on top of the North Tower, reported revenues of $37 million in 2000, making it the highest-grossing restaurant in the United States. The Twin Towers became known worldwide, appearing in movies, television shows, postcards, and other  merchandise. The towers came to be seen as a New York City icon, much like the Empire State Building, the Chrysler Building, and the Statue of Liberty. Incidents. On February 13, 1975, a three-alarm fire broke out on the 11th floor of the North Tower. The fire spread through the core of the building to the 9th and 14th floors, as the insulation for telephone cables, located in a utility shaft that ran vertically between floors, had been ignited. Areas most affected by the fire were extinguished almost immediately, and the original fire was put out in a few  hours. Most of the damage was on the 11th floor, where the fire was fueled by cabinets filled with paper, alcohol-based fluid for office machines, and other office equipment. Fireproofing protected the steel, and there was no structural damage to the tower. In addition to the fire damage on the 9th and 14th floors, water used to extinguish the fire damaged a few floors below. At the time, the World Trade Center complex had no fire sprinkler systems. The first terrorist attack on the World Trade Center occurred on February 26, 1993, at 12:17 p.m., when a Ryder truck  filled with of explosives, planted by Ramzi Yousef, detonated in the underground garage of the North Tower. The blast resulted in a hole through five sublevels. The greatest damage was on levels B1 and B2, with significant structural damage on level B3. Six people were killed, and more than a thousand were injured, as 50,000 workers and visitors were inside the tower at the time. Many people inside the North Tower were forced to walk down darkened stairwells that had no emergency lighting, and some took two hours or more to reach safety. Destruction. At 8:46 a.m. (EDT) on September  11, 2001, five hijackers affiliated with al-Qaeda crashed American Airlines Flight 11 into the northern facade of the North Tower between the 93rd and 99th floors. Seventeen minutes later, at 9:03 a.m. (EDT), a second group of terrorists crashed the hijacked United Airlines Flight 175 into the southern facade of the South Tower, striking between the 77th and 85th floors. By 9:59 a.m. (EDT), the South Tower collapsed after burning for approximately 56 minutes. After burning for 102 minutes, the North Tower collapsed due to structural failure at 10:28 a.m. (EDT). When the North Tower collapsed, debris fell on  the nearby 7 World Trade Center, damaging it and starting fires. The fires burned for hours, compromising the building's structural integrity. Seven World Trade Center collapsed at 5:21 p.m. (EDT). Together with a simultaneous attack on the Pentagon in Arlington, Virginia, and a failed plane hijacking that resulted in a plane crash in Shanksville, Pennsylvania, the attacks resulted in the deaths of 2,996 people (2,507 civilians, 343 firefighters, 72 law enforcement officers, 55 military personnel, and the 19 hijackers). More than 90% of the workers and visitors who died in the towers had been at or above the points  of impact. In the North Tower, 1,355 people at or above the point of impact were trapped, and died of smoke inhalation, fell, jumped from the tower to escape the smoke and flames, or were killed when the building eventually collapsed. One stairwell in the South Tower, Stairwell A, somehow avoided complete destruction, unlike the rest of the building. When Flight 11 hit, all three staircases in the North Tower above the impact zone were destroyed, thus making it impossible for anyone above the impact zone to escape. 107 people below the point of impact also died. Current building (2013 –present). History. Planning and early development. Following the destruction of the original World Trade Center, there was debate regarding the future of the World Trade Center site. There were proposals for its reconstruction almost immediately, and by 2002, the Lower Manhattan Development Corporation had organized a competition to determine how to use the site. The proposals were part of a larger plan to memorialize the September 11 attacks and rebuild the complex. Already the site was becoming a tourist attraction; in the year following the attacks the Ground Zero site became the most visited place in the United States. On  September 10, 2002, the Viewing Wall, a temporary display containing information about the attacks and listing the names of the dead, opened to the public. When the public rejected the first round of designs, a second, more open competition took place in December 2002, in which a design by Daniel Libeskind was selected as the winner in February 2003. Other designs were submitted by Richard Meier, Peter Eisenman, Charles Gwathmey, and Steven Holl; William Pedersen; and Foster and Partners. This design underwent many revisions, mainly because of disagreements with developer Larry Silverstein, who held the lease to the World Trade  Center site at that time. Peter Walker and Michael Arad’s “Reflecting Absence” proposal was selected as the site’s 9/11 Memorial in January 2004. There was criticism concerning the limited number of floors that were designated for office space and other amenities in an early plan. Only 82 floors would have been habitable, and the total office space of the rebuilt World Trade Center complex would have been reduced by more than in comparison with the original complex. The floor limit was imposed by Silverstein, who expressed concern that higher floors would be a liability in the event of  a future terrorist attack or other incident. Much of the building's height would have consisted of a large, open-air steel lattice structure on the roof of the tower, containing wind turbines and "sky gardens". In a subsequent design, the highest occupiable floor became comparable to the original World Trade Center, and the open-air lattice was removed from the plans. In 2002, former New York Governor George Pataki faced accusations of cronyism for supposedly using his influence to get the winning architect's design picked as a personal favor for his friend and campaign contributor, Ronald Lauder. A  final design for the "Freedom Tower" was formally unveiled on June 28, 2005. To address security issues raised by the New York City Police Department, a concrete base was added to the design in April of that year. The design originally included plans to clad the base in glass prisms in order to address criticism that the building might have looked uninviting and resembled a "concrete bunker". However, the prisms were later found to be unworkable, as preliminary testing revealed that the prismatic glass easily shattered into large and dangerous shards. As a result, it was replaced by a simpler  facade consisting of stainless steel panels and blast-resistant glass. Contrasting with Libeskind's original plan, the tower's final design tapers octagonally as it rises. Its designers stated that the tower would be a "monolithic glass structure reflecting the sky and topped by a sculpted antenna." In 2006, Larry Silverstein commented on a planned completion date: "By 2012 we should have a completely rebuilt World Trade Center, more magnificent, more spectacular than it ever was." On April 26, 2006, the Port Authority of New York and New Jersey approved a conceptual framework that allowed foundation construction to begin. A  formal agreement was drafted the following day, the 75th anniversary of the 1931 opening of the Empire State Building. Construction began in May; a formal groundbreaking ceremony took place when the first construction team arrived. Construction and later development. The symbolic cornerstone of One World Trade Center was laid in a ceremony on July 4, 2004. The stone had an inscription supposedly written by Arthur J. Finkelstein. However, construction was delayed until 2006 due to disputes over money, security, and design. The last major issues were resolved on April 26, 2006, when a deal was made between developer Larry Silverstein  and the Port Authority of New York and New Jersey, so the cornerstone was temporarily removed from the site on June 23, 2006. Soon after, explosives were detonated at the construction site for two months to clear bedrock for the building's foundation, onto which of concrete was poured by November 2007. In a December 18, 2006, ceremony held in nearby Battery Park City, members of the public were invited to sign the first steel beam installed onto the building's base. It was welded onto the building's base on December 19, 2006. Foundation and steel installation began shortly  afterward, so the tower's footings and foundation were nearly complete within a year. In January 2008, two cranes were moved onto the site. Construction of the tower's concrete core, which began after the cranes arrived, reached street level by May 17. However, construction of the base was not finished until two years later, after which construction of the office floors began, and the first glass windows were subsequently installed; during 2010, floors were constructed at a rate of about one per week. An advanced "cocoon" scaffolding system was installed to protect workers from falling, and was the first  such safety system installed on a steel structure in the city. The tower reached 52 floors and was over tall by December 2010. The tower's steel frame was halfway complete by then, but grew to 82 floors by the tenth anniversary of the September 11 attacks, at which time its concrete flooring had reached 72 floors and the glass cladding had reached 56 floors. In 2009, the Port Authority changed the official name of the building from "Freedom Tower" to "One World Trade Center", stating that this name was the "easiest for people to identify with." The “Freedom Tower ” name had also been subject to ridicule on programs like "Saturday Night Live." The name change also served a practical purpose: real estate agents believed that it would be easier to lease space in a building with a traditional street address. The change came after board members of the Port Authority voted to sign a 21-year lease deal with Vantone Industrial Co., a Chinese real estate company, which would become the building's first commercial tenant to sign a lease. Vantone plans to create the China Center, a trade and cultural facility, covering 191,000 square feet on floors 64  through 69. Detailed floor plans of the tower were posted on New York City's Department of Finance website in May 2011. This resulted in an uproar from the media and citizens of the surrounding area, who warned that the plans could potentially be used for a future terrorist attack. While under construction, the tower was specially illuminated on several occasions. On the weekend of July 4, 2011, it was lit up with the colors of the U.S. flag to commemorate Independence Day, and it was lit up with the same colors on September 11 to mark the 10th anniversary  of the September 11 terrorist attacks. On October 27 of that same year, it was illuminated with pink in honor of Breast Cancer Awareness Month. On December 11, the Port Authority illuminated the tower with multicolored lights to celebrate the holiday season. On February 24, 2012, the building was lit up with red in honor of Archbishop of New York Timothy Dolan, who became a cardinal on February 18. On June 14, 2012, it was illuminated with red, white, and blue to honor Flag Day. In August, it was illuminated with red in honor of the Armed Forces. On September  8, 2012, it was once again illuminated with red, white, and blue to honor the 11th anniversary of the September 11 attacks. On June 24, 2013, the building was again illuminated with red, white, and blue to celebrate the Fourth of July. The tower's loading dock, however, was not due to be finished in time to move equipment into the completed building, so five temporary loading bays were added at a cost of millions of dollars. The temporary PATH station was not to be removed until its official replacement, the World Trade Center Transportation Hub, was completed, blocking access  to the planned loading area. By March 2012, One World Trade Center's steel structure had reached 93 floors, growing to 94 floors and by the end of the month. However, because the floor numberings were based on standard measurements, the 94th floor was numbered "floor 100", because the extra space was occupied by the high-ceilinged 91st floor, which was used for mechanical purposes. The still-incomplete tower became New York City's tallest building by roof height in April 2012, passing the roof height of the Empire State Building. President Barack Obama visited the construction site two months  later and wrote, on a steel beam that would be hoisted to the top of the tower, the sentence "We remember, we rebuild, we come back stronger!" That same month, with the tower's structure nearing completion, the owners of the building began a public marketing campaign for the building, seeking to attract visitors and tenants. One World Trade Center's steel structure topped out at the nominal 104th floor, with a total height of , in August 2012. The tower's spire was then shipped from Quebec to New York in November 2012, and the first section of the spire  was hoisted to the top of the tower on December 12, 2012, and was installed on January 15, 2013. By March 2013, two sections of the spire had been installed. The spire's completion was scheduled for April 29, 2013, but bad weather delayed the delivery of the final pieces. On May 10, 2013, the final piece of the spire was lifted to the top of One World Trade Center, bringing the tower to its full height of , and making it the fourth-tallest building in the world at the time. In subsequent months, the exterior elevator shaft was removed ; the podium glass, interior decorations, and other finishings were being installed; and installation of concrete flooring and steel fittings was completed. A report in September 2013 revealed that, at the time of the report, the World Trade Center Association (WTCA) was negotiating with regard to the "World Trade Center" name, as the WTCA had purchased the rights to the name in 1986. The WTCA sought $500,000 worth of free office space in the tower in exchange for the use of "World Trade Center" in the tower's name and associated souvenirs. On November 12, 2013, the Height Committee of  the Chicago-based Council on Tall Buildings and Urban Habitat (CTBUH) made the controversial announcement that One World Trade Center was the tallest building in the United States at , declaring that the mast on top of the building is a spire since it is a permanent part of the building's architecture. By the same reasoning, the building was also the tallest in the Western Hemisphere. Opening and early years. On November 1, 2014, moving trucks started moving items for the tower's first occupying tenant, magazine publisher Condé Nast, from its old 4 Times Square headquarters to One World  Trade Center. "The New York Times" noted that the area around the World Trade Center had transitioned from a financial area to one with technology firms, residences, and luxury shops, coincident with the building of the new tower. The building opened on November 3, 2014, and Condé Nast employees moved into spaces spread among 24 floors. Condé Nast occupied floors 20 to 44, having completed its move in early 2015. It was expected that the company would attract new tenants to occupy the remaining 40% of unleased space in the tower, as Condé Nast had revitalized Times Square after moving  there in 1999. Only about 170 of 3,400 total employees moved into the new tower on the first day. At the time, future tenants included Kids Creative, Legends Hospitality, the BMB Group, Servcorp, and "GQ". By August 2020, Conde Nast indicated it wanted to leave One World Trade Center. This led Advance Publications, parent company of Conde Nast, to start withholding rent payments in January 2021. After a prolonged impasse, Conde Nast agreed to pay almost $10 million in back rent. Estimated cost and funding. An estimate in February 2007 placed the initial construction cost of One World Trade  Center at about $3 billion, or $1,150 per square foot ($12,380 per square meter). However, the tower's total estimated construction cost had risen to $3.9 billion by April 2012, making it the most expensive building in the world at the time. The tower's construction was partly funded by approximately $1 billion of insurance money that Silverstein received for his losses in the September 11 attacks. The State of New York provided an additional $250 million, and the Port Authority agreed to give $1 billion, which would be obtained through the sale  of bonds. The Port Authority raised prices for bridge and tunnel tolls to raise funds, with a 56 percent toll increase scheduled between 2011 and 2015; however, the proceeds of these increases were not used to pay for the tower's construction. Architecture and design. Many of Daniel Libeskind's original concepts from the 2002 competition were discarded from the tower's final design. One World Trade Center's final design consisted of simple symmetries and a more traditional profile, intended to compare with selected elements of the contemporary New York skyline. The tower's central spire draws from previous  buildings, such as the Empire State Building and the Chrysler Building. It also visually resembles the original Twin Towers, rather than being an off-center spire similar to the Statue of Liberty. One World Trade Center is considered the first major building whose construction is based upon a three-dimensional Building Information Model. The building occupies a square, with an area of , nearly identical to the footprints of the original Twin Towers. The tower is built upon a tall windowless concrete base, designed to protect it from truck bombs and other ground-level attacks. Originally, the base was to be  covered in decorative prismatic glass, but a simpler glass-and-steel façade was adopted when the prisms proved unworkable. The current base cladding consists of angled glass fins protruding from stainless steel panels, similar to those on 7 World Trade Center. LED lights behind the panels illuminate the base at night. Cable-net glass façades on all four sides of the building for the higher floors, designed by Schlaich Bergermann, will be consistent with the other buildings in the complex. The façades are high, and range in width from on the east and west sides, on the north side, and  on the south side. The curtain wall was manufactured and assembled by Benson Industries in Portland, Oregon, using glass made in Minnesota by Viracon. From the 20th floor upwards, the square edges of the tower's cubic base are chamfered back, shaping the building into eight tall isosceles triangles, or an elongated square antiprism. Near its middle, the tower forms a perfect octagon, and then culminates in a glass parapet, whose shape is a square oriented 45 degrees from the base. A 408-foot (124 m) sculpted mast containing the broadcasting antenna – designed in a collaboration between Skidmore, Owings and  Merrill (SOM), artist Kenneth Snelson (who invented the tensegrity structure), lighting designers, and engineers – is secured by a system of cables, and rises from a circular support ring, which contains additional broadcasting and maintenance equipment. At night, an intense beam of light is projected horizontally from the spire and shines over above the tower. David Childs of SOM, the architect of One World Trade Center, said the following regarding the tower's design: Layout. Just south of the new One World Trade Center is the National September 11 Memorial & Museum, which is located where the original Twin Towers stood. Immediately  to the east is World Trade Center Transportation Hub and the new Two World Trade Center site. To the north is 7 World Trade Center, and to the west is Brookfield Place. One World Trade Center's top floor is officially designated as floor 104, despite the fact that the tower only contains 94 actual stories. The building has 86 usable above-ground floors, of which 78 are intended for office purposes (approximately ). The base consists of floors 1–19, including a 65-foot-high (20 m) public lobby, featuring the 90-foot mural "" by American artist José Parlá. The office  floors begin at floor 20, and go up to floor 63. There is a sky lobby on floor 64; office floors resume on floor 65, and stop at floor 90. Floors 91–99 and 103–104 are mechanical floors. The tower has a three-story observation deck, located on floors 100–102, in addition to existing broadcast and antenna facilities. Its height is 1,268 feet (386.5 m), making it the highest vantage point in New York City. Similar to the Empire State Building, visitors to the observation deck and tenants have their own separate entrances; one entrance is on the West Street side  of the building, and the other is from within the shopping mall, descending down to a below-ground security screening area. On the observation deck, the actual viewing space is on the 100th floor, but there is a food court on the 101st floor and a space for events for the 102nd floor. To show visitors the city, and give them information and stories about New York, an interactive tool called City Pulse is used by Tour Ambassadors. The admission fee is $32 per person, but admission discounts are available for children and seniors, and the deck is free  for 9/11 responders and families of 9/11 victims. When it opened, the deck was expected to have about 3.5 million visitors per year. Tickets went on sale starting on April 8. However, the Manhattan District Attorney probed the Port Authority about the firm to which it awarded a contract to operate the deck. It officially opened on May 28, 2015, one day ahead of schedule. There are three eating venues at the top of the building: a café (called One Café); a bar and "small plates" grill (One Mix); and a fine dining restaurant (One Dining). Some have criticized the  food prices; the need of a full observatory ticket purchase to enter; and their reputations compared to Windows on the World, the top-floor restaurant in the original One World Trade Center. The tenants have access to below-ground parking, storage, and shopping; access to PATH, New York City Subway trains, and the World Financial Center is also provided at the World Trade Center Transportation Hub; /Fulton Center; and stations. The building allows direct access to West Street, Vesey Street, and Fulton Street at ground level. The building has an approximate underground footprint of , of which is retail space. A  plan to build a restaurant near the top of the tower, similar to the original One World Trade Center's Windows on the World, was abandoned as logistically impractical. The tower's window-washing tracks are located on a 16-square-foot area, which is designated as floor 110 as a symbolic reference to the 110 floors of the original tower. Design evolution. The original design went through significant changes after the Durst Organization joined the Port Authority of New York and New Jersey as the project’s co-developer in 2010. The tall base corners were originally designed to  gently slope upward and have prismatic glass. The corners were later squared. In addition, the base's walls are now covered in "hundreds of pairs of 13-foot vertical glass fins set against horizontal bands of eight-inch-wide stainless-steel slats." The spire was originally to be enclosed with a protective radome, described as a "sculptural sheath of interlocking fiberglass panels". However, the radome-enclosed spire was changed to a plain antenna. Douglas Durst, the chairman of the Durst Organization, stated that the design change would save $20 million. However, the tower's architect, Skidmore Owings & Merrill, strongly  criticized the change. David Childs, the lead designer, said, "Eliminating this integral part of the building's design and leaving an exposed antenna and equipment is unfortunate ... We stand ready to work with the Port on an alternate design." After joining the project in 2010, the Durst Organization had suggested eliminating the radome to reduce costs, but the proposal was rejected by the Port Authority's then-executive director, Christopher O. Ward. Ward was replaced by Patrick Foye in September 2011. Foye changed the Port Authority's position, and the radome was removed from the plans. In 2012, Douglas Durst  gave a statement regarding the final decision: "(the antenna) is going to be mounted on the building over the summer. There's no way to do anything at this point." The large triangular plaza on the west side of One World Trade Center facing the Hudson River was originally planned to have stainless steel steps descending to the street. However, the steps were changed to a terrace in the final design. The terrace can be accessed through a staircase on Vesey Street. The terrace is paved in granite, and has 12 sweetgum trees, in addition to a block-long planter /bench. Durst also removed a skylight from the plaza's plans; the skylight was designed to allow natural light to enter the below-ground observation deck lobby. The plaza is higher than the adjacent sidewalk. The Port Authority formally approved all these revisions, and the revisions were first reported by the "New York Post". Patrick Foye, the executive director of the Port Authority, said that he thought that the changes were "few and minor" in a telephone interview. A contract negotiated between the Port Authority and the Durst Organization states that the Durst Organization will receive a $15 million  fee and a percentage of "base building changes that result in net economic benefit to the project." The specifics of the signed contract give Durst 75% of the savings (up to $24 million) with further returns going down to 50%; 25%; and 15% as the savings increase. Height. The top floor of One World Trade Center is above ground level, along with a parapet; this is identical to the roof height of the original One World Trade Center. The tower's spire brings it to a pinnacle height of , a figure intended to symbolize the year 1776, when the  United States Declaration of Independence was signed. When the spire is included in the building's height, as stated by the Council on Tall Buildings and Urban Habitat (CTBUH), One World Trade Center surpasses the height of Taipei 101 (), is the world's tallest all-office building, and the sixth-tallest skyscraper in the world, behind the Burj Khalifa, Shanghai Tower, Abraj Al Bait, Ping An Finance Centre and Lotte World Tower. One World Trade Center is the second-tallest freestanding structure in the Western Hemisphere, as the CN Tower in Toronto exceeds One World Trade Center's pinnacle height  by approximately . The Chicago Spire, with a planned height of , was expected to exceed the height of One World Trade Center, but its construction was canceled due to financial difficulties in 2009. After design changes for One World Trade Center's spire were revealed in May 2012, there were questions as to whether the -tall structure would still qualify as a spire, and thus be included in the building's height. Since the tower's spire is not enclosed in a radome as originally planned, it could be classified as a simple antenna, which is not included in a building 's height, according to the CTBUH. Without the spire, One World Trade Center would be tall, making it the seventh-tallest building in the United States, behind the Trump International Hotel & Tower in Chicago. Upon completion, the building became the tallest in New York City with the antenna; however, without the antenna, it would have been surpassed in 2015 by 432 Park Avenue, which topped out at high. One World Trade Center's developers had disputed the claim that the spire should be reclassified as an antenna following the redesign, with Port Authority spokesman Steve Coleman reiterating that "One World  Trade Center will be the tallest building in the Western Hemisphere." In 2012, the CTBUH announced that it would wait to make its final decision as to whether or not the redesigned spire would count towards the building's height. On November 12, 2013, the CTBUH announced that One World Trade Center's spire would count as part of the building's recognized height, giving it a final height of 1,776 feet, and making it the tallest building in the Western Hemisphere. Sustainability. Like other buildings in the new World Trade Center complex, One World Trade Center includes sustainable architecture  features. Much of the building's structure and interior is built from recycled materials, including gypsum boards and ceiling tiles; around 80 percent of the tower's waste products are recycled. Although the roof area of any tower is limited, the building implements a rainwater collection and recycling scheme for its cooling systems. The building's PureCell phosphoric acid fuel cells generate 4.8 megawatts (MW) of power, and its waste steam generates electricity. The New York Power Authority selected UTC Power to provide the tower's fuel cell system, which was one of the largest fuel cell installations in the  world once completed. The tower also makes use of off-site hydroelectric and wind power. The windows are made of an ultra-clear glass, which allows maximum sunlight to pass through; the interior lighting is equipped with dimmers that automatically dim the lights on sunny days, reducing energy costs. Like all of the new facilities at the World Trade Center site, One World Trade Center is heated by steam, with limited oil or natural gas utilities on-site. One World Trade Center received a Leadership in Energy and Environmental Design (LEED) Gold Certification, making it one of the most environmentally  sustainable skyscrapers in the world. Security features. Along with the protection provided by the reinforced concrete base, a number of other safety features were included in the building's design, so that it would be prepared for a major accident or terrorist attack. Like 7 World Trade Center, the building has thick reinforced concrete walls in all stairwells, elevator shafts, risers, and sprinkler systems. There are also extra-wide, pressurized stairwells, along with a dedicated set of stairwells exclusively for the use of firefighters, and biological and chemical filters throughout the ventilation system. In comparison, the original Twin Towers used  a purely steel central core to house utility functions, protected only by lightweight drywall panels. The building is no longer away from West Street, as the Twin Towers were; at its closest point, West Street is away. The Port Authority has stated: "Its structure is designed around a strong, redundant steel moment frame consisting of beams and columns connected by a combination of welding and bolting. Paired with a concrete-core shear wall, the moment frame lends substantial rigidity and redundancy to the overall building structure while providing column-free interior spans for maximum flexibility." In addition to safety design , new security measures were implemented. All vehicles will be screened for radioactive materials and other potentially dangerous objects before they enter the site through the underground road. Four hundred closed-circuit surveillance cameras will be placed in and around the site, with live camera feeds being continuously monitored by the NYPD. A computer system will use video-analytic computer software, designed to detect potential threats, such as unattended bags, and retrieve images based on descriptions of terrorists or other criminal suspects. New York City and Port Authority police will patrol the site. Before the World Trade Center site was fully  completed, the plaza was not completely opened to the public, as the original World Trade Center plaza was. The initial stage of the opening process began on Thursday, May 15, 2014, when the "Interim Operating Period" of the National September 11 Memorial ended. During this period, all visitors were required to undergo airport style security screening, as part of the "Interim Operating Period", which was expected to end on December 31, 2013. However, screening did not fully end until the official dedication and opening of the museum on May 21, 2014, after which visitors were allowed to use the plaza  without needing passes. Incidents. In March 2014, the tower was scaled by 16-year-old Weehawken, New Jersey resident Justin Casquejo, who entered the site through a hole in a fence. He was subsequently arrested on trespassing charges. He allegedly dressed like a construction worker, sneaked in, and convinced an elevator operator to lift him to the tower's 88th floor, according to news sources. He then used stairways to get to the 104th floor, walked past a sleeping security guard, and climbed up a ladder to get to the antenna, where he took pictures for two hours. The elevator  operator was reassigned, and the guard was fired. It was then revealed that officials had failed to install security cameras in the tower, which facilitated Casquejo's entry to the site. Casquejo was sentenced to 23 days of community service as a result. Reception. The social center of the previous One World Trade Center included a restaurant on the 107th floor, called Windows on the World, and The Greatest Bar on Earth; these were tourist attractions in their own right, and a gathering spot for people who worked in the towers. This restaurant also housed one of the most prestigious  wine schools in the United States, called "Windows on the World Wine School", run by wine personality Kevin Zraly. Despite numerous assurances that these attractions would be rebuilt, the Port Authority scrapped plans to rebuild them, which has outraged some observers. The fortified base of the tower has also been a source of controversy. Some critics, including Deroy Murdock of the "National Review", have said that it is alienating and dull, and reflects a sense of fear rather than freedom, leading them to dub the building "the Fear Tower". Nicolai Ouroussoff, the architecture critic for "The New York Times", calls  the tower base a "grotesque attempt to disguise its underlying paranoia". Owners and tenants. One World Trade Center is principally owned by the Port Authority of New York and New Jersey. Around 5 percent equity of the building was sold to the Durst Organization, a private real estate company, in exchange for an investment of at least $100 million. The Durst Organization assisted in supervising the building's construction, and manages the building for the Port Authority, having responsibility for leasing, property management, and tenant installations. By September 2012, around 55 percent of the building's floor space had  been leased, but no new leases were signed for three years until May 2014; the amount of space leased had gone up to 62.8 percent by November 2014. In 2006, the State of New York agreed to a 15-year lease, with an option to extend the lease's term and occupy up to . The General Services Administration (GSA) initially agreed to a lease of around , and New York State's Office of General Services (OGS) planned to occupy around . However, the GSA ceded most of its floor space to the Port Authority in July 2011, and the OGS withdrew  from the lease contract. In April 2008, the Port Authority announced that it was seeking a bidder to operate the observation deck on the tower's 102nd floor; in 2013, Legends Hospitality Management agreed to operate the observatory in a 15-year, $875 million contract. The building's first lease, a joint project between the Port Authority and Beijing-based Vantone Industrial, was announced on March 28, 2009. A "China Center", combining business and cultural facilities, is planned between floors 64 and 69; it is intended to represent Chinese business and cultural links to the United States, and to  serve American companies that wish to conduct business in China. Vantone Industrial's lease is for 20 years and 9 months. In April 2011, a new interior design for the China Center was unveiled, featuring a vertical "Folding Garden", based on a proposal by the Chinese artist Zhou Wei. On August 3, 2010, Condé Nast Publications signed a tentative agreement to move the headquarters and offices for its magazines into One World Trade Center, occupying up to of floor space. On May 17, 2011, Condé Nast reached a final agreement with the Port Authority, securing a 25-year lease with  an estimated value of $2 billion. On May 25, 2011, Condé Nast finalized the lease contract, obtaining of office space between floors 20–41. The lease also includes of usable space in the podium and below grade floors, for mail, messenger services, and storage use. On January 17, 2012, it was reported that Condé Nast would be leasing an additional of space, occupying floors 42 through 44. Conde Nast moved in on November 3, 2014. However, some leases failed. In January 2012, Chadbourne & Parke, a Midtown Manhattan-based law firm, was to sign a lease contract, but after negotiations broke  down, the deal was abruptly canceled in March. In August 2014, it was announced Servcorp signed a 15-year lease for , taking the entire 85th floor. Servcorp subsequently sublet all of its space on the 85th floor as private offices, boardrooms and co-working space to numerous medium-sized businesses such as ThinkCode, D100 Radio, and Chérie L'Atelier des Fleurs. Key figures. Developer. Larry Silverstein of Silverstein Properties, the leaseholder and developer of the complex, retains control of the surrounding buildings, while the Port Authority has full control of the tower itself. Silverstein signed a 99-year lease for the  World Trade Center site in July 2001, and remains actively involved in most aspects of the site's redevelopment process. Before construction of the new tower began, Silverstein was involved in an insurance dispute regarding the tower. The terms of the lease agreement signed in 2001, for which Silverstein paid $14 million, gave Silverstein, as leaseholder, the right and obligation to rebuild the structures if they were destroyed. After the September 11 attacks, there were a series of disputes between Silverstein and insurance companies concerning the insurance policies that covered the original towers; this resulted in the construction of  One World Trade Center being delayed. After a trial resulted, a verdict was given on April 29, 2004. The verdict was that ten of the insurers involved in the dispute were subject to the "one occurrence" interpretation, so their liability was limited to the face value of those policies. Three insurers were added to the second trial group. At that time, the jury was unable to reach a verdict on one insurer, Swiss Reinsurance, but it did so several days later on May 3, 2004, finding that this company was also subject to the "one occurrence" interpretation. Silverstein appealed the  Swiss Reinsurance decision, but the appeal failed on October 19, 2006. The second trial resulted in a verdict on December 6, 2004. The jury determined that nine insurers were subject to the "two occurrences" interpretation, referring to the fact that two different planes had destroyed the towers during the September 11 attacks. They were therefore liable for a maximum of double the face value of those particular policies ($2.2 billion). The highest potential payout was $4.577 billion, for buildings 1, 2, 4, and 5. In March 2007, Silverstein appeared at a rally of construction workers and public officials  outside an insurance industry conference. He highlighted what he describes as the failures of insurers Allianz and Royal & Sun Alliance to pay $800 million in claims related to the attacks. Insurers state that an agreement to split payments between Silverstein and the Port Authority is a cause for concern. Key project coordinators. David Childs, one of Silverstein's favorite architects, joined the project after Silverstein urged him to do so. He developed a design proposal for One World Trade Center, initially collaborating with Daniel Libeskind. In May 2005, Childs revised the design to address security concerns. He is the  architect of the tower, and is responsible for overseeing its day-to-day design and development. Architect Daniel Libeskind won the invitational competition to develop a plan for the new tower in 2002. He gave an initial proposal, which he called "Memory Foundations", for the design of One World Trade Center. His design included aerial gardens, windmills, and off-center spire. Libeskind later denied a request to place the tower in a more rentable location next to the PATH station. He instead placed it another block west, as it would then line up with, and resemble, the Statue of Liberty . Most of Libeskind's original designs were later scrapped, and other architects were chosen to design the other WTC buildings. However, one element of Libeskind's initial plan was included in the final design – the tower's symbolic height of . Daniel R. Tishman – along with his father John Tishman, builder of the original World Trade Center – led the construction team from Tishman Realty & Construction, the selected builder for One World Trade Center. Douglas and Jody Durst, the co-presidents of the Durst Organization, a real estate development company, won the right to invest at least $100 million in the  project on July 7, 2010. In August 2010, Condé Nast, a long-time Durst tenant, confirmed a tentative deal to move into One World Trade Center, and finalized the deal on May 26, 2011. The contract negotiated between the Port Authority and the Durst Organization specifies that the Durst Organization will receive a $15 million fee, and a percentage of "base building changes that result in net economic benefit to the project". The specifics of the signed contract give Durst 75 percent of savings up to $24 million, stepping down to 50, 25, and 15 percent as savings  increase. Since Durst joined the project, significant changes have been made to the building, including the 185 foot base of the tower, the spire, and the plaza to the west of the building, facing the Hudson River. The Port Authority has approved all the revisions. Port Authority construction workers. A WoodSearch Films short-subject documentary entitled "How does it feel to work on One World Trade Center?" was uploaded to YouTube on August 31, 2010. It depicted construction workers who were satisfied with the working conditions at the construction site. However, further analysis of the work site showed that dozens  of construction-related injuries had occurred at the site during the construction of One World Trade Center, including 34 not reported to the U.S. Occupational Safety and Health Administration. Workers also left post-9/11-related graffiti at the site, which are supposed to symbolize rebirth and resilience.