September 11 attacks

A coordinated terrorist attack by al-Qaeda that hijacked four passenger airliners and killed nearly 3,000 people in the United States on September 11, 2001.

American Airlines Flight 11: A Boeing 767 hijacked by al-Qaeda operatives and flown into the World Trade Center's North Tower. Its impact began the attacks in New York and killed everyone aboard and many inside the tower.
Al-Qaeda: A transnational Islamist militant organization founded by Osama bin Laden and others in the late 1980s. The organization planned and carried out the September 11 attacks.
War on Terror: A U.S.-led global campaign of counterterrorism launched after the September 11 attacks. The attacks supplied the defining impetus and political mandate for the campaign.
National September 11 Memorial & Museum: A memorial and museum at the World Trade Center site in New York City commemorating the September 11 attacks and 1993 bombing. Its names, artifacts, and exhibits preserve the attacks' human toll and historical record.
United Airlines Flight 175: A Boeing 767 hijacked by al-Qaeda operatives and flown into the World Trade Center's South Tower. Its impact, broadcast live, made the attacks' deliberate nature unmistakable.
Osama bin Laden: The founder and leader of al-Qaeda, who claimed responsibility for the September 11 attacks. He approved the operation and framed it as retaliation against U.S. policies.
Authorization for Use of Military Force of 2001: A U.S. law authorizing force against those responsible for the September 11 attacks and those who harbored them. Congress enacted it to authorize the military response to the attacks.
Pentagon Memorial: A memorial in Arlington, Virginia, honoring the 184 people killed at the Pentagon and aboard Flight 77. It commemorates the victims at one of the attacks' three impact sites.
American Airlines Flight 77: A Boeing 757 hijacked by al-Qaeda operatives and crashed into the Pentagon. It carried the attack from New York to the United States' military headquarters.
Khalid Sheikh Mohammed: A senior al-Qaeda figure who devised the aircraft-hijacking plot and helped organize its execution. His proposal became the operational blueprint for the attacks.

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