Photos: Photos: One World Trade Center towers over NYC One World Trade Center towers over NYC – Ironworkers wait for the final piece of the One World Trade Center spire to be raised into position for attachment to the building in New York on Friday, May 10. The 408-foot spire brings the building to a height of 1,776 feet, making it the tallest in the Western Hemisphere. Hide Caption 1 of 27

Photos: Photos: One World Trade Center towers over NYC One World Trade Center towers over NYC – The One World Trade Center with the newly installed spire towers over the New York skyline on May 10. Hide Caption 2 of 27

Photos: Photos: One World Trade Center towers over NYC One World Trade Center towers over NYC – The spire is perched on a temporary platform on the top of One World Trade Center on Thursday, May 2. The memorial building sits on ground zero, the site of the World Trade Center twin towers, which were destroyed in the September 11 terrorist attacks. Hide Caption 3 of 27

Photos: Photos: One World Trade Center towers over NYC One World Trade Center towers over NYC – Construction workers watch as the 408-foot spire is hoisted onto a temporary platform on the top of One World Trade Center. Hide Caption 4 of 27

Photos: Photos: One World Trade Center towers over NYC One World Trade Center towers over NYC – An ironworker uses a line to steady the final piece of the spire. Hide Caption 5 of 27

Photos: Photos: One World Trade Center towers over NYC One World Trade Center towers over NYC – The final section of the spire is raised to the top of One World Trade Center. Hide Caption 6 of 27

Photos: Photos: One World Trade Center towers over NYC One World Trade Center towers over NYC – People watch as the final section of the spire is raised to the top of One World Trade Center. Hide Caption 7 of 27

Photos: Photos: One World Trade Center towers over NYC One World Trade Center towers over NYC – Weather delayed the morning delivery of the final two sections of a 408-foot spire to the top of One World Trade Center on Monday, April 29, according to the Port Authority of New York and New Jersey. Hide Caption 8 of 27

Photos: Photos: One World Trade Center towers over NYC One World Trade Center towers over NYC – Cranes surround the new building on April 2 during the last stages of the construction. Hide Caption 9 of 27

Photos: Photos: One World Trade Center towers over NYC One World Trade Center towers over NYC – Manhattan is seen from One World Observatory from the 100th floor of 1 World Trade Center on April 2. Hide Caption 10 of 27

Photos: Photos: One World Trade Center towers over NYC One World Trade Center towers over NYC – Workers prepare the first piece of the spire to be hoisted atop the One World Trade Center on December 12. Hide Caption 11 of 27

Photos: Photos: One World Trade Center towers over NYC One World Trade Center towers over NYC – Parts of the spire for the new skyscraper make their way on a barge from Port Newark to Lower Manhattan on December 11. Hide Caption 12 of 27

Photos: Photos: One World Trade Center towers over NYC One World Trade Center towers over NYC – The "Tribute in Light" shines near the spots where the twin towers once stood as red, white and blue light up the new building on the 11th anniversary of the attacks. Hide Caption 13 of 27

Photos: Photos: One World Trade Center towers over NYC One World Trade Center towers over NYC – Ironworkers walk around the steel decking on the 100th story of the building on April 12, 2012. Hide Caption 14 of 27

Photos: Photos: One World Trade Center towers over NYC One World Trade Center towers over NYC – Ironworker Steven Cross carries steel cable across the top of the building on April 30, 2012. Hide Caption 15 of 27

Photos: Photos: One World Trade Center towers over NYC One World Trade Center towers over NYC – Construction continues on One World Trade Center on August 12, 2011, beside the memorial footprints of the twin towers. Hide Caption 16 of 27

Photos: Photos: One World Trade Center towers over NYC One World Trade Center towers over NYC – A worker uses a blowtorch to cut metal near the temporary top floor of One World Trade Center on March 9, 2011. Hide Caption 17 of 27

Photos: Photos: One World Trade Center towers over NYC One World Trade Center towers over NYC – Construction continues on September 8, 2010. Hide Caption 18 of 27

Photos: Photos: One World Trade Center towers over NYC One World Trade Center towers over NYC – A worker stands on a scaffolding near the base of the construction on December 9, 2010. Hide Caption 19 of 27

Photos: Photos: One World Trade Center towers over NYC One World Trade Center towers over NYC – The superstructure of One World Trade Center is seen at ground zero on August 3, 2009. Hide Caption 20 of 27

Photos: Photos: One World Trade Center towers over NYC One World Trade Center towers over NYC – Work continues on the concrete core of the building December 9, 2008. Hide Caption 21 of 27

Photos: Photos: One World Trade Center towers over NYC One World Trade Center towers over NYC – An excavator moves protective mats into position over the hole where test blasts were fired in preparation for the footings of what was then called Freedom Tower on June 12, 2006. Hide Caption 22 of 27

Photos: Photos: One World Trade Center towers over NYC One World Trade Center towers over NYC – The site model of lower Manhattan with the Freedom Tower as designed by David Childs was on display at the Winter Garden on September 6, 2006, in New York. Hide Caption 23 of 27

Photos: Photos: One World Trade Center towers over NYC One World Trade Center towers over NYC – Architect David Childs speaks beside a model design of the Freedom Tower on June 28, 2005, in New York. Hide Caption 24 of 27

Photos: Photos: One World Trade Center towers over NYC One World Trade Center towers over NYC – Cleanup continues on August 27, 2002, nearly a year after the attacks. Hide Caption 25 of 27

Photos: Photos: One World Trade Center towers over NYC One World Trade Center towers over NYC – Firefighters make their way over the ruins through clouds of smoke at ground zero on October 11, 2001. Hide Caption 26 of 27