On the morning of Sept. 11, 2001, a plane sped across the New York City skyline and crashed into the World Trade Center, igniting a series of terrorist attacks that left more than 3,000 Americans dead.
Learn more about the attacks, hear memories, watch video of the original Channel One News broadcast and learn what happened that morning in our timeline.
The World Trade Center was a complex of office buildings that opened in lower Manhattan in 1973.
This 1990 photo shows the New York City skyline with World Trade Center's twin towers in the center, before the towers crumbled, before the smoke billowed and the planes hit.
(AP Photo, File)
American Airlines Flight 11 out of Boston, Massachusetts crashes into the North Tower of the World Trade Center.
Emergency responders begin their rush to the scene. News stations around the country begin broadcasting live footage of the towers.
United Airlines Flight 175 approaches the south tower of the World Trade Center in New York shortly before collision as smoke billows from the north tower.
(AP Photo/Carmen Taylor)
Chief of Staff Andy Card whispers into the ear of President George W. Bush to give him word of the plane crashes into the World Trade Center, during a visit to the Emma E. Booker Elementary School in Sarasota, Fla.
(AP Photo/Doug Mills, File)
American Airlines Flight 77 crashes into the Pentagon.
Pedestrians in lower Manhattan watch smoke rise from the World Trade Tower.
Television brought the attacks to the world in real time, and linked the thousands who lived through it and the millions who watched. It became a collective experience and one of the most digitally documented events ever.
(AP Photo/Amy Sancetta)
The south tower of the World Trade Center begins to collapse after the attack.
(AP Photo/Amy Sancetta)
A fourth plane, United Flight 93, crashed in a field in Shanksville, Pennsylvania.
The passengers on that flight fought back against the terrorists who had hijacked the plane and likely saved hundreds of lives by preventing the plane from crashing into another landmark.
The North Tower of the World Trade Center collapses.
Mayor Rudolph Guiliani calls for the evacuation of lower Manhattan.
These people, covered in the dust that was created by the collapsing buildings, walk over debris near the World Trade Center in New York.
(AP Photo/Gulnara Samoilova)
A shell of what was once part of the facade of one of the twin towers of New York's World Trade Center rises above the rubble that remains after both towers were destroyed in the terrorist attacks.
(AP Photo/Shawn Baldwin, File)
President George W. Bush addresses the nation.
An excerpt from his speech:
"Today, our fellow citizens, our way of life, our very freedom came under attack in a series of deliberate and deadly terrorist acts. The victims were in airplanes or in their offices: secretaries, business men and women, military and federal workers, moms and dads, friends and neighbors. Thousands of lives were suddenly ended by evil, despicable acts of terror.
The pictures of airplanes flying into buildings, fires burning, huge -- huge structures collapsing have filled us with disbelief, terrible sadness, and a quiet, unyielding anger. These acts of mass murder were intended to frighten our nation into chaos and retreat. But they have failed. Our country is strong.
A great people has been moved to defend a great nation."
An American flag flies over the rubble of the World Trade Center in New York.
(AP Photo/Beth A. Keiser, file)