911 days separated the September 11 terrorist attacks on the U.S. and the 2004 train bombings in Madrid, Spain.
The winning numbers in a New York state lottery drawing on 11 September 2002 were 9-1-1.
The date of the attack: 9/11 - 9 + 1 + 1 = 11
September 11th is the 254th day of the year: 2 + 5 + 4 = 11
After September 11th there are 111 days left to the end of the year.
Twin Towers - standing side by side, looks like the number 11
The first plane to hit the towers was Flight 11
But ....There's More.......
State of New York - The 11th State added to the Union
New York City - 11 Letters
Afghanistan - 11 Letters
The Pentagon - 11 Letters
Ramzi Yousef - 11 Letters (convicted of orchestrating the attack on the WTC in 1993)
Flight 175 - 65 on board - 6 + 5 = 11
Not that this all means anything, just some interesting numbers.