The term "9/11" refers to the terrorist attacks that occurred on September 11, 2001, in the United States. On that morning, 19 Al Qaeda terrorists hijacked four commercial passenger planes. Two of these planes were flown into the Twin Towers of the World Trade Center in New York City, causing both towers to collapse. A third plane crashed into the Pentagon near Washington, D.C., and the fourth plane crashed in rural Pennsylvania after passengers attempted to regain control from the hijackers, preventing it from hitting another target, possibly the White House
. These attacks resulted in nearly 3,000 deaths and had a profound impact globally. In response, the U.S. launched the "War on Terror," including an invasion of Afghanistan to dismantle al-Qaeda and remove the Taliban regime that harbored them. This marked a significant shift in U.S. and global security policies, with increased focus on counterterrorism and new anti- terror legislation in many countries
. The attacks exposed vulnerabilities in U.S. national security and intelligence coordination, prompting major reforms to improve information sharing and government organization to better prevent future attacks. The 9/11 Commission Report details the events, the failures in government response, and lessons learned to enhance national security
. The aftermath saw extensive rescue and recovery efforts, including the U.S. Army Corps of Engineers' rapid response to aid evacuation and support emergency operations in New York City
. The attacks also deeply affected the American public and leadership, with President George W. Bush guiding the national response during this crisis
. In summary, 9/11 was a coordinated terrorist attack that fundamentally changed U.S. and global approaches to security, counterterrorism, and foreign policy, with lasting consequences still felt today
