The events of September 11, 2001, often referred to as 9/11, were a series of coordinated terrorist attacks carried out by the extremist group al-Qaeda on the United States. These attacks had a profound and lasting impact on the world.

Here is a chronological overview of the events of 9/11 and what immediately followed.

Morning of September 11, 2001: At 8:46 AM (Eastern Daylight Time), American Airlines Flight 11, a Boeing 767, crashed into the North Tower of the World Trade Center in New York City. This was the first of four planes hijacked by terrorists. At 9:03 AM, United Airlines Flight 175, another Boeing 767, crashed into the South Tower of the World Trade Center. At 9:37 AM, American Airlines Flight 77, a Boeing 757, was crashed into the Pentagon in Arlington, Virginia. At 10:03 AM, United Airlines Flight 93, a Boeing 757, crashed into a field in Shanksville, Pennsylvania, after passengers attempted to regain control of the plane from the hijackers. It is believed that this plane was heading for a target in Washington, D.C.

Immediate Response: In response to the attacks, the Federal Aviation Administration (FAA) ordered the grounding of all domestic flights in the United States, resulting in the closure of airspace. Law enforcement and emergency services personnel rushed to the scenes of the attacks in New York City, Washington, D.C., and Pennsylvania to assist with rescue and recovery efforts. President George W. Bush, who was in Florida at the time, addressed the nation and vowed to bring those responsible to justice.

Worldwide Reaction: Countries around the world expressed shock and solidarity with the United States. Many governments offered their support and condolences. NATO invoked Article 5 for the first time in its history, declaring the attacks on the United States to be an attack on all NATO member states, leading to an outpouring of support from its allies.

Investigation and Attribution: The U.S. government quickly identified the terrorist organization al-Qaeda, led by Osama bin Laden, as responsible for the attacks. A comprehensive investigation was launched, leading to the identification of the 19 hijackers and their connections to al-Qaeda.

War on Terror: In the aftermath of 9/11, the United States initiated the "War on Terror." The U.S. military, along with coalition forces, launched the invasion of Afghanistan in October 2001 to dismantle al-Qaeda and remove the Taliban regime from power. The U.S. and its allies implemented various security measures and reforms to prevent future terrorist attacks, including the creation of the Department of Homeland Security.

Memorials and Commemoration: Numerous memorials and ceremonies have been held to commemorate the victims of 9/11, including the construction of the 9/11 Memorial and Museum at the World Trade Center site in New York City.

The events of 9/11 had a profound and lasting impact on the United States and the world, leading to significant changes in domestic and international policies, security measures, and the way nations approached the threat of terrorism. The memory of 9/11 continues to shape global politics and security strategies to this day.

Click here to print this worksheet. Answer Key: (1) extremist group al-Qaeda; (2) b. False; (3) invasion of Afghanistan in October 2001 to dismantle al-Qaeda and remove the Taliban regime from power; (4) Department of Homeland Security; (5) see map below.