The World Trade Center's twin towers are destroyed, and the Pentagon and U.S. Capitol are targeted by al-Qaeda by using U.S. passenger planes as bombs.

Approximately 3,000 people are killed. For the first time, the U.S. invokes Article 5 of the North Atlantic Treaty Organization (NATO), demanding its allies fight on its behalf.

Motives for the attack that are named include the United States' support of Israel, sanctions against Iraq, and other imperialist tactics employed by the U.S.

After the attack, Islamophobia increases across the U.S., including increased violence against Arab and Muslim communities, as well as the heightened surveillance of social justice organizations that are pro-Palestine and anti-policing, whose activities are increasingly seen as "acts of terrorism."