That morning, two planes crashed into the World Trade Center in New York City, one plane into each tower. Both towers collapsed within two hours. The pilot of the third team crashed a plane into the Pentagon in Arlington County, Virginia.

During this attack 2,973 people died and another 24 remain missing as a result of these attacks. Three buildings in the World Trade Center Complex collapsed due to structural failure on the day of the attack. The south tower fell at approximately 9:59 a.m., after burning for 58 minutes in a fire caused by the impact of United Airlines Flight 175 at 9:03 a.m.. The north tower fell at 10:28 a.m., after burning approximately 103 minutes in a fire caused by the impact of American Airlines Flight 11 at 8:45 a.m.. A third building, 7 World Trade Center also collapsed at 5:30 p.m., after burning for at least 70 minutes and being heavily damaged by debris from the Twin Towers a short distance away.

The attacks created massive confusion across the United States. During the course of the day, unconfirmed and often contradictory reports were aired and published.

The attacks had major global political ramifications. They were denounced by mainstream media and governments worldwide. Approximately one month after the attacks, the United States led a broad coalition of international forces to invade Afghanistan in pursuit of al-Qaeda forces in order to topple the Taliban regime for harboring what it referred to as a terrorist organization.

Since the attacks, various theories have emerged. These include speculation that individuals in the government of the United States knew of the impending attacks and failed to act on that knowledge, or that they actually planned the attacks.