The question "how did 9" appears incomplete, but based on common related queries, it likely refers to "how did 9/11 happen?" or "how did 9/11 attacks occur?" The 9/11 terrorist attacks occurred on the morning of September 11, 2001, when 19 Al Qaeda terrorists hijacked four commercial passenger planes in the United States. Two planes were flown into the Twin Towers of the World Trade Center in New York City, causing both towers to collapse. A third plane was crashed into the Pentagon near Washington, DC. The fourth plane crashed in rural Pennsylvania after passengers fought the hijackers, preventing it from hitting its intended target, believed to be the White House. These coordinated attacks killed nearly 3,000 people and caused massive destruction. The attacks were masterminded by the terrorist group Al Qaeda under Osama bin Laden, who sought to inflict massive casualties and symbolic damage to the US. The event led to the US declaring the "War on Terror," including the invasion of Afghanistan to dismantle Al Qaeda and remove the Taliban regime that harbored them.

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