I believe this artwork depicts America's Unity and is a Tribute to the Heroes and to All the People Who Lost Their Lives on September 11, 2001.
This is signed by the artist and is one of his NYC Art Series. Limited Edition 2001. Size: 19 3/4"L x 12 1/2"w x 1 1/4"d. Excellent condition. The paper on the back is a little wrinkled.