The World Trade Center south tower burst into flames after being struck by hijacked United Airlines Flight 175 as the north tower burns following an earlier attack by a hijacked airliner on Sept. 11, 2001, in New York City.
Sean Adair, Reuters
The Pentagon is seen in the aftermath of the Sept. 11, 2001, terror attacks. More than 200 people died there, including 64 people on the hijacked plane that crashed into the building.
Laura Farr, ZUMA Press Wire
Smoke rises behind investigators as they comb the crater left by the crash of United Airlines flight 93 on Sept. 12, 2001, near Shanksville, Pennsylvania. Flight 93 is one of four planes hijacked as part of a deadly and destructive terrorist plot against the U.S.
Tim Shaffer, Reuters
A September 14, 2001 file photo shows U.S. President George W. Bush talks to retired firefighter Bob Beckwith (R) from Ladder 117 at the scene of the World Trade Center disaster in New York. Bush, who was in office at the time of the Sept. 11 attacks and famously said he wanted Osama bin Laden dead or alive, said on Sunday the death of the al Qaeda leader was a "momentous achievement." "The fight against terror goes on, but tonight America has sent an unmistakable message: No matter how long it takes, justice will be done," Bush said in a statement. REUTERS/Win McNamee/Files (UNITED STATES - Tags: DISASTER CRIME LAW POLITICS IMAGES OF THE DAY)
Melvin Brenzy of Ronco, Pennsylvania (L) and Betty Kotila of Hanover Park, Illinois (R) examine wooden angels at the Flight 93 Temporary Memorial near Shanksville, Pennsylvania on September 10, 2003. The angels memorialize the forty people killed when United Airlines Flight 93 crashed in Shanksville two years ago. The victims will be remembered in ceremonies on September 11 marking the two-year anniversary of the attacks on New York, Washington DC and Pennsylvania. REUTERS/Jason Cohn JC
