The document provides an overview of the 9/11 terrorist attacks and their aftermath. It discusses how 19 hijackers took control of 4 planes on September 11, 2001, crashing two into the World Trade Center towers, one into the Pentagon, and one into a field in Pennsylvania. Nearly 3,000 people were killed. The US blamed Al-Qaeda and invaded Afghanistan, where Osama bin Laden was killed in 2011. The attacks had major health, economic, and social impacts both in the US and globally, increasing distrust of Muslims. Some researchers and theorists have argued US agencies had advance knowledge or were complicit in the attacks.