One World Trade Center (also known as 1 World Trade Center, One WTC and 1 WTC; the current building was dubbed the “Freedom Tower” during initial basework) refers to the main building of the new World Trade Center complex in Lower Manhattan, New York City. It is the tallest skyscraper in the Western Hemisphere, and the fourth-tallest in the world. The 104-story supertall structure shares a numeric name with the northern Twin 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 16-acre (6.5 ha) World Trade Center site, on the site of the original 6 World Trade Center. The building is bordered by West Street to the west, Vesey Street to the north, Fulton Street to the south, and Washington Street to the east.
Construction of below-ground utility relocations, footings, and foundations for the new building began on April 27, 2006. On March 30, 2009, the Port Authority of New York and New Jersey 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.
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 new World Trade Center complex will initially include three other high-rise office buildings, which will be built along Greenwich Street, and 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.
The top floor of One World Trade Center is 1,368 feet (417 m) above ground level, along with a 33 ft 4 in (10.16 m) parapet; this is identical to the roof height of the original One World Trade Center. The tower’s antenna/spire brings it to a pinnacle height of 1,776 feet (541 m), a figure intended to symbolize the year 1776, when the United States Declaration of Independence was signed. If the antenna 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 (1,671-foot (509 m)), is the world’s tallest all-office building, and the fourth-tallest skyscraper in the world, behind the Burj Khalifa, Abraj Al Bait, and Shanghai Tower.
One World Trade Center is the second-tallest freestanding structure in the Western Hemisphere, as the CN Tower in Toronto exceeds 1 WTC’s pinnacle height by approximately 12 m (39.4 ft). The Chicago Spire, with a planned height of 2,000 feet (610 m), was expected to exceed the height of One World Trade Center, but its construction was canceled due to financial difficulties in 2009. (Description from Wikipedia)