Trade Center) 北楼 (North
Tower) 。9点03分时，联合航空的这家飞机则撞上世界贸易中心的南楼 (South
September 11, 2001, is a day that no one will forget. It began as a crystal clear, blue-sky Tuesday. As mid-morning approached, however, the brightness quickly turned into tragedy. American Airlines Flight 11 left Boston, Massachusetts, at 8 a.m., bound for Los Angeles, California. At 8:14 a.m., United Airlines Flight 175 also left Boston for Los Angeles. At 8:45 a.m., just 45 minutes after taking off, the American jet crashed into the World Trade Center's North Tower in New York City. At 9:03 a.m., the United jet crashed into the World Trade Center's South Tower. By 10:30 a.m. both towers had collapsed completely from the damage.
As people watched these events unfold on television, they were frightened and bewildered. It quickly became obvious that the United States was under attack and that the airliners were being used as weapons by hijackers.