<P> The building's architect was 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 1,776 feet (541 m). 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 . </P> <P> 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 is 104 standard floors high, but the tower has only 94 actual stories . </P> <P> 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 . </P> <P> 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 . Yamasaki 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 . </P>

What is the purpose of the one world trade center