Twenty-five years after theSept. 11 terrorist attacks, the nation is preparing to mark a solemn milestone. Nearly 3,000 people were killed on Sept. 11, 2001, when al-Qaida terrorists hijacked four commercial airliners and crashed them into the World Trade Center, the Pentagon and a field outside Shanksville, Pennsylvania.
For millions of Americans, 9/11 remains a defining national tragedy. But nearly 30% of U.S. residents were born after 2001, meaning many know the attacks only through history lessons, memorials and the stories of survivors. As the nation commemorates the 25th anniversary with ceremonies and tributes, here's what to know about the attacks, who carried them out and the legacy they left behind.
years ago. They're still shaping our lives
What happened on 9/11?
What began as an ordinary Tuesday morning became one of the deadliest days in American history.
At 8:46 a.m., hijackers crashed American Airlines Flight 11 into the North Tower of the World Trade Center in New York City. Minutes later, United Airlines Flight 175 struck the South Tower. A third hijacked plane, American Airlines Flight 77, slammed into the Pentagon, while a fourth aircraft, United Airlines Flight 93, crashed in Pennsylvania after passengers fought back against the attackers.
Millions watched in horror as the attacks unfolded live on television and both Twin Towers collapsed within hours.
Who planned the 9/11 attacks?
The Sept. 11 attacks were planned and carried out by al-Qaida, the terrorist network led by Osama bin Laden.
Federal investigators say the plot was orchestrated by Khalid Sheikh Mohammed, with bin Laden and al-Qaida deputy Ayman al-Zawahri overseeing the operation. Nineteen hijackers carried out the attacks, led by Mohamed Atta, who piloted American Airlines Flight 11 into the North Tower of the World Trade Center.
The hijackers spent months preparing for the coordinated attack and began entering the United States as early as 2000.
Bin Laden went into hiding after 9/11 and was killed by U.S. forces in Pakistan in 2011. Al-Zawahri was killed in a U.S. drone strike in Afghanistan in 2022. Khalid Sheikh Mohammed remains imprisoned at Guantanamo Bay, where he and three co-defendants are scheduled to face a military tribunal in 2028.
How many people died on 9/11
A total of 2,977 people were killed in the Sept. 11 attacks, not including the 19 hijackers, according to the 9/11 Memorial & Museum. It remains the deadliest foreign attack ever carried out on U.S. soil.
- World Trade Center: 2,753 deaths, including hundreds of first responders.
- Pentagon: 184 deaths, including passengers, crew and Pentagon employees.
- Flight 93: 40 deaths after passengers fought back against the hijackers.
Who was president during 9/11?
George W. Bush was serving his first term as president when the attacks occurred.
Bush was visiting an elementary school in Sarasota, Florida, when Chief of Staff Andrew Card informed him that planes had struck the World Trade Center. He later addressed the nation as the scale of the attacks became clear.
Who was New York City's mayor during 9/11?
Rudy Giuliani was mayor of New York City during the attacks.
Giuliani became a national figure as he helped lead the city through the immediate aftermath and recovery effort, earning the nickname "America's Mayor."
How many planes were hijacked?
Four commercial airplanes were hijacked on Sept. 11, 2001.
Two were flown into the Twin Towers, one struck the Pentagon, and the fourth, United Airlines Flight 93, crashed in Pennsylvania after passengers attempted to stop the hijackers.
Why does 9/11 still matter 25 years later?
Twenty-five years later, the attacks continue to shape American life, from airport security and counterterrorism policy to the nation's collective memory.
As the U.S. marks the anniversary, memorial ceremonies across the country will honor the victims and ensure a new generation understands the events that changed America forever.
Contributing: Susan Page, Christopher Cann, Phaedra Trethan / USA TODAY
Saman Shafiq is a trending news reporter for USA TODAY. Reach her at sshafiq@gannett.com and follow her on X and Instagram @saman_shafiq7.
This article originally appeared on USA TODAY: What happened on 9/11? A look back 25 years
