9/11 Attacks: 25 Years Later, A Day That Changed the World

September 11, 2026, marks 25 years since the terrorist attacks that killed nearly 3,000 people in the United States and profoundly changed the course of modern history.

Across the United States, the anniversary is being observed with ceremonies, memorials and flags flown at half-staff as families, survivors and communities remember those who lost their lives on September 11, 2001.

Known as 9/11, the attacks were a series of four coordinated terrorist attacks carried out by 19 al-Qaeda hijackers. The hijackers seized four commercial passenger aircraft travelling from the U.S. East Coast to California.

Two of the aircraft were deliberately crashed into the North and South Towers of the World Trade Center in New York City. A third aircraft was flown into the Pentagon, the headquarters of the U.S. Department of Defense, in Arlington, Virginia.

The fourth aircraft, United Airlines Flight 93, crashed in a rural area near Shanksville, Pennsylvania, after passengers and crew attempted to regain control of the plane. The aircraft did not reach its intended target in Washington, D.C.

The attacks killed 2,977 people, making September 11 one of the deadliest terrorist attacks in history. Victims included civilians, firefighters, police officers, emergency workers and people aboard the four aircraft.

A Turning Point in Global History

The attacks triggered an extraordinary response from the United States and its allies. The U.S. launched a global campaign against al-Qaeda and other groups designated as terrorist organisations, beginning with military action in Afghanistan against the Taliban regime that had provided sanctuary to al-Qaeda.

The subsequent “War on Terror” expanded over the following decades, including the 2003 U.S.-led invasion of Iraq and military operations and counterterrorism campaigns in several other countries.

The attacks also transformed security and surveillance policies in the United States. In the aftermath, policymakers and the public debated far-reaching measures involving national identification, intelligence operations, overseas counterterrorism actions and expanded government surveillance powers.

Remembering 25 Years Later

A quarter of a century after 9/11, its impact continues to be felt by survivors, families of victims, emergency responders and communities around the world.

For those who experienced the attacks and their aftermath, September 11 remains a deeply personal day of remembrance. For younger generations who were not yet born in 2001, the anniversary offers an opportunity to understand an event that reshaped international relations, security policy and the lives of millions.

Twenty-five years later, the names of the victims continue to be remembered, while memorials across the United States stand as enduring reminders of the lives lost and the profound consequences of that September morning.