The September 11 attacks, often referred to as 9/11, were a series of four coordinated terrorist attacks by the Wahhabi terrorist group Al-Qaeda against the United States on the morning of Tuesday, September 11, 2001. The attacks resulted in 2,977 fatalities, over 25,000 injuries, and substantial long-term health consequences, in addition to at least $10 billion in infrastructure and property damage. It is the deadliest terrorist attack in human history and the deadliest incident for firefighters and law enforcement officers in the history of the United States, with 340 and 72 killed, respectively.
Four passenger airliners which had departed from airports in the northeastern United States bound for California were hijacked by 19 al-Qaeda terrorists. Two of the planes, American Airlines Flight 11 and United Airlines Flight 175, crashed into the North and South towers, respectively, of the World Trade Center complex in Lower Manhattan. Within an hour and 42 minutes, both 110-story towers collapsed.