20.
Andrew Lichtenstein / Getty Images
Crowds swarm over the Manhattan Bridge to leave Manhattan on the morning of the Sept. 11 attack.
19.
Jose Jimenez / Primera Hora / Getty Images
A firefighter runs into the street as the World Trade Center crumbles behind him.
18.
New York Daily News Archive / Getty Images
New York Daily News staff photographer David Handschuh takes refuge in a storefront after being injured by falling debris.
17.
Angela Jimenez / Getty Images
A survivor kneels in horror and disbelief outside the World Trade Center.
16.
Ron Agam / Getty Images
A vehicle sits on its side amid rubble at the World Trade Center.
15.
Mario Tama / Getty Images
A firefighter breaks down during a brief moment of rest.
14.
Mario Tama / Getty Images
Civilians take cover as a dust cloud from the collapse of the World Trade Center envelops lower Manhattan.
13.
Chung Sung-jun / Getty Images
A man in Seoul watches a multiscreen broadcast of the attack on the World Trade Center.
12.
New York Daily News Archive / Getty Images
A firefighter covered with ash is helped toward shelter after the World Trade Center collapse.
11.
Handout / Getty Images
President George W. Bush, Vice President Dick Cheney, and National Security Advisor Condoleezza Rice meet in the Emergency Operations Center after the attacks.