并有中文翻译,最好在100字内！
參考答案:The September 11, 2001, attacks (often referred to as 9/11—pronounced "nine eleven") consisted of a series of coordinated suicide terrorist[1] attacks upon the United States, predominantly targeting civilians, carried out on Tuesday, September 11, 2001.
That morning, 19 terrorists[2] affiliated with al-Qaeda[3] hijacked four commercial passenger jet airliners. Each team of hijackers included a trained pilot. Two planes (United Airlines Flight 175 and American Airlines Flight 11) crashed into the World Trade Center in New York City, one plane into each tower (One and Two). Both towers collapsed within two hours. The pilot of the third team crashed American Airlines Flight 77 into the Pentagon in Arlington County, Virginia. Passengers and members of the flight crew on the fourth aircraft (United Airlines Flight 93) attempted to retake control of their plane from the hijackers; that plane crashed into a field near the town of Shanksville in rural Somerset County, Pennsylvania. As well as the 19 hijackers, a confirmed 2,973 people died and another 24 are missing but presumed killed as a result of these attacks.
九一一袭击事件，简称“九一一事件”或“九一一”，是2001年9月11日发生在美国本土，通过劫持多架民航飞机冲撞摩天高楼的自杀式恐怖袭击。在事件中共有2,986人死亡，包括美国纽约地标性建筑世界贸易中心双塔在内的6座建筑被完全摧毁，其它23座高层建筑遭到破坏，美国国防部总部所在地五角大楼也受到袭击，美国经济同样遭到严重打击。该事件也导致了此后国际范围内的反恐行动，包括了阿富汗战争和伊拉克战争以及针对恐怖组织及相关国家越来越大的压力。
这次事件是自1944年10月日本向美国抛下“风船炸弹”以来美国本土第二次遭受来自空中的袭击，也是继珍珠港事件后，历史上第二次外国势力对美国本土造成惨重伤亡的袭击，事件中死亡的总人数已经超过珍珠港事件中的2,400人。