This still image obtained September 10, 2012, from IntelCenter shows Ayman al-Zawahiri speaking from an undisclosed location. IntelCenter/AFP via Getty Images hide caption
9/11 attacks
President George W. Bush stands in the rubble of the World Trade Center in New York and speaks to workers involved in the cleanup effort on Sept. 14, 2001. Doug Mills/AP hide caption
An Nguyen sits for a portrait at George Mason University in Fairfax, Va. Nguyen had just turned four when his father died in the 9/11 attack on the Pentagon. Ian Morton/NPR hide caption
They Don't Remember Their Parents Dying On 9/11. But They'll Never Forget
Khalid Sheikh Mohammed, seen shortly after his capture during a 2003 raid in Pakistan, is accused of masterminding the Sept. 11, 2001, terrorist attacks that killed nearly 3,000 people. AP hide caption
Rep. Ilhan Omar, D-Minn., attends a Youth Climate Strike on March 15 in Washington. On Thursday, the New York Post drew criticism after featuring a partial quote by Omar with an image from the Sept. 11, 2001, terrorist attacks. Tom Brenner/Getty Images hide caption
Supreme Court Rules Post-9/11 Detainees Can't Sue Top U.S. Officials
An artist's rendering provided by Dutch architectural company MVRDV of its design for two skyscrapers in Seoul. AP hide caption
A fireman walks amongst the rubble and the smoldering wreckage of the World Trade Center in New York in the wake of the Sept. 11, 2001, attacks. Gary Friedman/AFP/Getty Images hide caption
Former Secretary of State Colin Powell, during an address in Washington, D.C., on March 1, 2010. Jim Watson/AFP/Getty Images hide caption
Sept. 13, 2001: An American flag, put there by rescue workers, stands in the wreckage of the World Trade Center. Chris Hondros/Getty Images hide caption
Sept. 11, 2001: A surveillance camera image of two men identified by authorities as Mohammed Atta (R) and Abdulaziz Alomari (C) at the Portland International Jetport. Getty Images hide caption