Four commercial planes crashed in different locations in the morning of September 11, 2001. Two planes hit the Towers in New York, one crashed into the Pentagon, and the fourth plane fell in a field. These incidents resulted in nearly 3,000 deaths. The attacks were carried out by 19 hijackers from the Islamist group al Qaeda.

The response to the attacks was swift and had lasting effects. Afghanistan, believed to be a refuge for al Qaeda, was invaded a month later, starting a nearly 20-year war. Iraq was also invaded in 2003. Further details about the impact of the 9/11 attacks are available from the source.

The aftermath of the attacks is still being felt today, with the effects of the US response still perceptible.