New to 9/11
An introduction to the events of September 11, 2001 — what happened, why it matters, and how we remember.
If you were born after 2001, you may be learning about September 11th for the first time. That's okay. This page is here to help you understand what happened that day, why it changed America, and why it's important to remember.
September 11, 2001 — often called simply “9/11” — was the deadliest terrorist attack in American history. It was a day that brought unimaginable loss, but also extraordinary acts of courage and unity.
What Happened on September 11, 2001
On the morning of September 11, 2001, 19 terrorists hijacked four commercial airplanes departing from airports on the East Coast of the United States.
Two of the planes were deliberately crashed into the Twin Towers of the World Trade Center in New York City, causing both 110-story buildings to collapse. A third plane was crashed into the Pentagon, the headquarters of the U.S. Department of Defense near Washington, D.C. The fourth plane, Flight 93, was headed toward Washington, D.C., but passengers and crew fought back against the hijackers, and the plane crashed into a field near Shanksville, Pennsylvania.
2,977 people lost their lives that day — office workers, firefighters, police officers, emergency medical technicians, military personnel, airline passengers and crew, and many others. Thousands more were injured, and the effects on survivors, families, and first responders continue to this day.
A Timeline of That Day
American Airlines Flight 11 departs Boston's Logan Airport bound for Los Angeles with 92 people on board.
United Airlines Flight 175 departs Boston's Logan Airport bound for Los Angeles with 65 people on board.
American Airlines Flight 77 departs Washington Dulles Airport bound for Los Angeles with 64 people on board.
United Airlines Flight 93 departs Newark Airport bound for San Francisco with 44 people on board.
Flight 11 crashes into the North Tower of the World Trade Center.
Flight 175 crashes into the South Tower of the World Trade Center. America realizes the nation is under attack.
Flight 77 crashes into the western side of the Pentagon.
The South Tower of the World Trade Center collapses.
Flight 93 crashes in a field near Shanksville, Pennsylvania, after passengers and crew heroically storm the cockpit to prevent the plane from reaching its intended target.
The Heroes of September 11th
In the midst of the attacks, ordinary people performed extraordinary acts of bravery. Firefighters, police officers, and emergency workers rushed into burning buildings to save others. 343 FDNY firefighters, Port Authority police officers, and NYPD officers gave their lives that day.
On Flight 93, passengers made phone calls to loved ones, learned that other planes had been used as weapons, and made the courageous decision to fight back. Their actions prevented the plane from reaching its intended target in Washington, D.C.
In the days and weeks that followed, thousands of volunteers traveled to New York, the Pentagon, and Shanksville to help with rescue and recovery. Communities across America came together in a spirit of unity that transcended every difference.
How It Changed America
September 11th changed the United States in profound and lasting ways. In the immediate aftermath, the country experienced an extraordinary sense of unity. Neighbors helped neighbors, strangers comforted one another, and communities rallied together.
The attacks also led to significant changes in national security, including the creation of the Department of Homeland Security and the Transportation Security Administration (TSA). Airport security procedures were fundamentally transformed.
Perhaps most importantly, 9/11 inspired a renewed commitment to public service. In the years that followed, record numbers of Americans volunteered for military service, joined fire departments and police forces, and engaged in community service. September 11th is now recognized as a National Day of Service and Remembrance.
The 9/11 National Memorial Trail
The 9/11 National Memorial Trail is a 1,500++ mile hiking and biking route that connects the three sites of the September 11th attacks: the National September 11 Memorial & Museum in New York City, the Pentagon Memorial in Arlington, Virginia, and the Flight 93 National Memorial in Shanksville, Pennsylvania.
The trail was conceived just five days after September 11, 2001, as a way to create a living memorial — one that people can experience with every step and every mile. It passes through 7 states and connects communities in remembrance, honor, and healing.
In 2021, the 9/11 National Memorial Trail was officially designated by Congress, recognizing its significance as a national monument to unity and resilience.
Learn More
These resources from the official memorial sites and trusted educational organizations can help you learn more about September 11th.
National September 11 Memorial & Museum
The official memorial and museum at the World Trade Center site in New York City.
Visit SitePentagon Memorial
Honoring the 184 lives lost at the Pentagon on September 11, 2001.
Visit SiteFlight 93 National Memorial
Honoring the 40 passengers and crew of United Flight 93.
Visit Site9/11 Memorial & Museum Education
Lesson plans, teaching guides, and educational materials for students and teachers.
Visit SiteKeep Learning
Understanding what happened on September 11th helps us honor those we lost and carry forward the spirit of unity that brought America together.