Talk about an important event from US History.Why is the event significant?

题目

Talk about an important event from US History.Why is the event significant?
还得再麻烦一下,如上提问,大约120字左右就行,

答案

911 events refers to the fact that on the United States Eastern timeSeptember 11,2001 morning,TheTerrorists hijacked 4 civilian airliners to hit New York's World Trade Centerand the Pentagon in Washin...