What major event occurred on September 11, 2001?

The major event that occurred on September 11, 2001, is the 9/11 Terrorist Attacks. On that day, a series of coordinated attacks carried out by the extremist group al-Qaeda led to the hijacking of four commercial airplanes. Two of these planes were flown into the Twin Towers of the World Trade Center in New York City, resulting in the collapse of both towers and significant loss of life. A third plane struck the Pentagon, the headquarters of the United States Department of Defense, while the fourth plane, United Airlines Flight 93, was brought down by passengers in Pennsylvania after it was diverted from its intended target.

The impact of these attacks was profound, fundamentally altering U.S. domestic and foreign policy and leading to the War on Terror. The event is often seen as a watershed moment in contemporary history, evoking a global response and significant changes to national security protocols. Understanding the significance of this event is crucial for grasping the context of current events and ongoing discussions about security, terrorism, and international relations.