I think graffiti is one of the most influential movements in art period. Graffiti revolutionized street art, through graffiti art became a thrill, something "forbidden" or frowned upon by society. This gave artist in New York and across the world a way to rebel against society and issues of which they were offended by. Many of these pieces on trains, walls & buildings were looked upon as great masterpieces especially to other graffiti artist of the time.
I have some images from my personal "Blackbook" from 2010 (a book were you practice your tags and let other taggers "throw up" their piece in)
The artist include Maze(Tats Cru), Nicer (Tats Cru), Bio (Tats Cru), Leos, Dose, Toxic, & Clue7.
|(Bio - Tats Cru)|
|(Nicer - Tats Cru)|
|(Maze - Tats Cru)|