<P> On November 12, 2014, the supporting wire rope cables of a suspended working platform slacked . The cables were manufactured by Tractel, and they were used to hold workers who performed maintenance on the building's exterior . At the time, the platform was holding a two - man, SEIU - affiliated window washing team . The slack caused the platform to hang almost vertically near the 68th floor of the tower . The workers were rescued by over 100 FDNY firefighters, who used a diamond saw to cut through the glass . After the incident, the workers suffered from a slight case of hypothermia, and were taken to the hospital . </P> <P> 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 . </P> <P> 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 . </P> <P> The building occupies a 200 - foot (61 m) square, with an area of 40,000 square feet (3,700 m), nearly identical to the footprints of the original Twin Towers . The tower is built upon a 185 - foot (56 m) 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 60 feet (18 m) high, and range in width from 30 feet (9.1 m) on the east and west sides, 50 feet (15 m) on the north side, and 70 feet (21 m) on the south side . The curtain wall was manufactured and assembled by Benson Industries in Portland, Oregon, using glass made in Minnesota by Viracon . </P>

How tall is the one world trade center memorial