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FILE- In this Sept. 17, 2001 file photo, the ruins of the World Trade Center continue to smolder almost a week after the Sept. 11 terrorist attack. Surrounding buildings were heavily damaged by the debris and massive force of the falling twin towers. While some feel that "Ground Zero" is the real estate that the World Trade Center occupied before falling in the 2001 terrorist attacks, others recognize an area that extends beyond the fence and into its lower Manhattan neighborhood. (AP Photo/U.S. Navy, Chief Photographer's Mate Eric J. Tilford, File)

FILE- In this Sept. 17, 2001 file photo, the ruins of the World Trade Center continue to smolder almost a week after the Sept. 11 terrorist attack. Surrounding buildings were heavily damaged by the debris and massive force of the falling twin towers. While some feel that "Ground Zero" is the real estate that the World Trade Center occupied before falling in the 2001 terrorist attacks, others recognize an area that extends beyond the fence and into its lower Manhattan neighborhood.