The skyscraper is being built according to a revised design released in June 2005. The new design retains essential elements of the original plan-- soaring 1,776 feet into the sky, its illuminated mast evoking the Statue of Liberty's torch -- but features a smaller, cubic base set back further from West Street to protect the building against future attacks. Rising from its square base -- which will be constructed of impermeable concrete and steel -- the redesigned Freedom Tower will taper into eight tall isosceles triangles, forming a perfect octagon at its center. An observation deck will be located 1,362 feet above ground and there will be a square glass parapet at 1,368 feet, the heights of the original Twin Towers. From these, an illuminated spire containing a television antenna will rise to a final height of 1,776 feet. Other key elements include; 2.6 million square feet of office space, tenant amenity spaces, world-class restaurants, below-grade retail, and access to the PATH, subway, and World Financial Center. According to the Port Authority schedule, the tower is expected to open in the fourth quarter of 2013.