We know you are just making stupid comments and don't care.
Many will say September 11, 2001. The answer as far as the United States is concerned is 1979, 22 years prior to September 2001, with the following attacks on us:
* Iran Embassy Hostages, 1979;
* Beirut , Lebanon Embassy 1983;
* Beirut , Lebanon Marine Barracks 1983;
* Lockerbie, Scotland Pan-Am flight to New York 1988;
* First New York World Trade Center attack 1993;
* Dhahran , Saudi Arabia Khobar Towers Military complex 1996;
* Nairobi , Kenya US Embassy 1998;
* Dares Salaam , Tanzania US Embassy 1998;
* A! den, Yemen USS Cole 2000;
* New York World Trade Center 2001;* Pentagon 2001.