9/11 Remembered2006 Freedom Walk Commemorates 9/11 Attacks On PentagonARLINGTON, VA - SEPTEMBER 10: A blue light illuminates the Pentagon September 10, 2006 in Arlington, Virginia. The Pentagon plans reportedly to also beam 184 lights skyward for each of the victims of the attack on the Pentagon September 11, 2001 during the nights of September 10th and 11th to commemorate the 5th anniversary of the terror attacks on the United States. (Photo by Brendan Smialowski/Getty Images)
9/11 RememberedNew York City Marks 11th Anniversary Of September 11th Attacks<> on September 11, 2012 in New York City.
9/11 RememberedNew York City Marks 11th Anniversary Of September 11th AttacksManhattan, New York -- September 11, 2012 --- A flag atop one of the panels around the north pool during observances held on the eleventh anniversary of the attacks on the World Trade Center, at the site in New York, September 11, 2012. -- CHRIS PEDOTA / THE RECORD / POOL
9/11 RememberedGates Leads Pentagon Memorial Observance Of 9/11WASHINGTON - SEPTEMBER 11: A memorial flag is illuminated near the spot on the side of the Pentagon that was hit by American Airlines Flight 77 on 9/11, September 11, 2007 in Washington, DC. Secretary of Defense Robert Gates is scheduled to host the Pentagon a memorial observance for family members of those who were killed in the September 11, 2001 attack on the Pentagon. (Photo by Brandan W. Schulze/U.S. Navy via Getty Images)
9/11 RememberedUS President Barack Obama and First LadyUS President Barack Obama and First Lady Michelle Obama arrive for a commemoration ceremony at the Flight 93 National Memorial on the 10th anniversary of the 9/11 attacks in Shanksville, Pennsylvania. AFP PHOTO/Mandel NGAN (Photo credit should read MANDEL NGAN/AFP/Getty Images)
9/11 RememberedConstruction Continues On One World Trade Center<> on May 16, 2013 in New York City.