Terrorist Attacks in the U.S.

im sure there have been hundreds of terroer attacks in the united states but the biggest one im sure was the attack of the world trade center in New york on september 11, 2001. on september 11 th 2 planes crashed into the twin towers and changed the history of america forever, thousands of people died that day and effected the lives of millions. on september 11th 2001 i was in the 2nd grade i remember them calling all the teachers out into the halls and telling them what happened when m,y teacher came back into the room she was crying and none of the younger kids knew what was happening but all the parents came to pick up their kids early that day. to be completly honest i dont really know why it happened. To try and prevent such a horrible thing from happening again airports allover the worlds have raised security to a higher level and i think the government is more careful about how they handle things