What major event occurred on September 11, 2001, in the United States?

On September 11, 2001, a coordinated series of terrorist attacks were carried out by the extremist group al-Qaeda against the United States. This event is one of the most significant and devastating in American history, as it involved hijacking four commercial airplanes. Two of the planes were flown into the World Trade Center towers in New York City, leading to their eventual collapse, while another plane struck the Pentagon, the headquarters of the U.S. Department of Defense. The fourth plane, United Airlines Flight 93, was headed for another target in Washington, D.C., but passengers attempted to regain control, resulting in it crashing in a field in Pennsylvania.

This tragic day resulted in the loss of nearly 3,000 lives and led to profound changes in U.S. foreign and domestic policy, including the initiation of the War on Terror and the establishment of the Department of Homeland Security. It is a pivotal point in contemporary history that reshaped global relations and posed new challenges to national and international security. Understanding this event provides valuable context for discussions around terrorism, national security measures, and the socio-political landscape in the United States in the years that followed.