911 Artwork, handed to me on a street corner

Below is the front and back of a 911 artwork. I was standing on a street corner and a man just walked up and handed it to me and walked away. It is one of my favorites pieces I have.

911 is 911.

I was to fly to New York for work on Sept 13 of that year. I ended up driving down with a friend for two weeks of work out in New Jersey.  On Oct 13 I started to fly across the United States to work. In Chicago my Hotel was quarantined for an Anthrax scare.  My flight to Reagan Airport changed to Arlington as you could not fly to Reagan as to close to Washington itself. Marines with machine guns and FBI or CIA boarded plane after it landed in Los Angeles and just took a man and walked him onto tarmate and into black van with no windows and just drove away.
Arlington, West Virginia was my first time that I had my carry on bags not asked to be opened but swiped with little white paper discs and then then placed in a computer and than said I could go through to gate. The entire thing watched by military with machine guns and German shepherds at their sides.


What does it all mean today?