September 11 attacks
Coordinated al-Qaeda suicide hijackings killed nearly 3,000 people.
Nineteen terrorists hijacked four airliners, crashing two into the Twin Towers of the World Trade Center in New York City, one into the Pentagon in Arlington County, Virginia, and the fourth into a field near Shanksville, Pennsylvania, after a passenger revolt.
- location
- United States (New York City; Arlington County, Virginia; Shanksville, Pennsylvania)
- perpetrator
- al-Qaeda
- ringleader
- Mohamed Atta
- known_for
- Deadliest terrorist attack in history; triggered the global war on terror
Lore & Background
The Federal Aviation Administration ordered a ground stop for all U.S. airspace traffic, and Canada's Operation Yellow Ribbon supported diverted aircraft. That evening, the CIA informed President George W. Bush that al-Qaeda under bin Laden was responsible. The U.S. launched the war on terror, invading Afghanistan, and NATO invoked Article 5 for the first time. The war in Afghanistan continued for another decade.
Reader's Guide
The September 11 attacks reshaped global security and foreign policy. The U.S. launched the global war on terror, invading Afghanistan and later Iraq, and NATO invoked Article 5 for the only time in its history. Many countries strengthened anti-terrorism legislation and expanded law enforcement and intelligence powers. The attacks caused long-term health consequences, serious economic harm to the U.S., and global market shocks. The Costs of War Project estimated that total deaths from the attacks and directly incited conflicts exceeded 4.5 million. Memorials include the National September 11 Memorial & Museum in New York, the Pentagon Memorial, and the Flight 93 National Memorial.
Did You Know?
- The fourth plane, United Airlines Flight 93, crashed in a Pennsylvania field after passengers revolted against the hijackers.
- The Costs of War Project estimated that total deaths from the attacks and directly incited conflicts exceeded 4.5 million.
Frequently Asked Questions
What are the September 11 attacks?
On September 11, 2001, al-Qaeda operatives seized control of four commercial aircraft and deliberately crashed them into major U.S. targets. Two planes struck the Twin Towers of the World Trade Center in New York City, a third hit the Pentagon in Arlington, Virginia, and the fourth went down in a field near Shanksville, Pennsylvania.
Who was behind the September 11 attacks?
The plot was organized by the terrorist network al-Qaeda, with Mohamed Atta serving as the lead hijacker and operational coordinator. Nineteen individuals carried out the coordinated hijackings across the four flights.
How many people were killed in the September 11 attacks?
Nearly 3,000 people lost their lives in the coordinated attacks, making it the deadliest terrorist act in recorded history. Victims included passengers aboard the planes, office workers in the towers, military and civilian personnel at the Pentagon, and first responders.
What happened to the fourth plane on September 11?
After passengers and crew on United Airlines Flight 93 learned what had occurred to the other aircraft, they staged a revolt against the hijackers. The plane crashed into a field near Shanksville, Pennsylvania, and no one aboard survived, but the attack on its intended target was thwarted.
Why are the September 11 attacks considered so historically significant?
The attacks killed nearly 3,000 people in a single day and fundamentally reshaped U.S. foreign and domestic policy. They directly triggered the global war on terror, leading to the invasions of Afghanistan and Iraq and a permanent transformation of security infrastructure worldwide.
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