Which war started as a consequence of the September 11 2001 attack and why?

The war that started as a consequence of the September 11, 2001 attacks is the Afghanistan War. The U.S. launched military operations in Afghanistan in October 2001 to dismantle al-Qaeda and remove the Taliban from power, as they were harboring Osama bin Laden and other al-Qaeda terrorists responsible for the attacks. The goal was to eradicate terrorist threats and prevent future attacks on American soil.