NEW YORK, NY - MAY 15:  Former New York Mayor Rudolph Giuliani speaks during the dedication ceremony in Foundation Hall at the National September 11 Memorial Museum at ground zero May 15, 2014 in New York City. The museum spans seven stories, mostly underground, and contains artifacts from the attack on the World Trade Center Towers on September 11, 2001 that include the 80-foot high tridents, the so-called 'Ground Zero Cross,' the destroyed remains of Company 21's New York Fire Department Engine as well as smaller items such as letter that fell from a hijacked plane and posters of missing loved ones projected onto the wall of the museum. The museum will open to the public on May 21. (Photo by Richard Drew-Pool/Getty Images)