Keith Haring is one of the most famous street artists of all time. Even if you've never heard of him, odds are you've seen his work memorialized on clothing, and other merchandise. He came from the same culture of "pop art" as Andy Warhol and others. Haring made a huge impact on the art world, despite dying at the far-too-young age of 31, in 1990.
Haring, in particular, left his mark on the street art in scene in NYC, and was one of the first to elevate the underground, illegal graffiti culture into something popular and mainstream. His most lasting NYC legacy is the Bowery Mural, a large wall on the corner of The Bowery & Houston Street. In 1982, he put a huge mural on the wall on that corner. He made the corner famous. Though that work is long-gone, that wall had become synonymous with art, and as the ownership of the building changed hands, and development grew around it, it was understood that the wall would need to remain a canvas for NYC's street artists. New murals now are painted on that wall seasonally.
However, one famous Haring piece in NYC remains. In 1986, Haring went to a random playground in east Harlem, and painted two murals, one on each side of a handball wall, to highlight the need to fight that era's crack epidemic. Not for the first time, Haring was arrested for vandalism. But the public and the press rallied around him, and he was let off with only a $100 fine. After the piece was itself vandalized, the Parks Dept asked Haring to come back and officially re-create his "Crack is Wack" mural. He did, and it remains today. It became so popular, that, after his death, the city officially renamed the entire playground the Crack Is Wack Playground.
And Haring's legacy remains on every other wall in NYC where street artists look to make their mark, and create a legitimacy to this form of art.