The query "why did 9" is very ambiguous, but it seems related to the events of 9/11, the terrorist attacks on September 11, 2001. To clarify the core of the likely question "Why did 9/11 happen?" here is a comprehensive explanation: The 9/11 attacks were orchestrated by the Islamist extremist network al-Qaeda, led by Osama bin Laden. The motivations behind the attacks included al-Qaeda's opposition to U.S. foreign policies in the Middle East, particularly U.S. military presence in Saudi Arabia after the Gulf War, support for Israel, and perceived injustices against Muslims worldwide. The attacks were a product of extreme ideology fueled by political and social grievances, economic conditions, and radicalization. Nineteen hijackers trained in the U.S. carried out the attacks on the World Trade Center, the Pentagon, and the failed attempt resulting in a crash in Pennsylvania. The consequences of 9/11 reshaped U.S. policies and global geopolitics extensively.
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