Author Norman Mailer published an essay in which he declared the graffiti(涂鸦) of the New York subway to be "The Great Art of the 70s". But what happened to the artists and why is there no subway graffiti any more?

　　"It started with someone just writing their name - someone saw that, and added on to it," recalls New York graffiti artist Nicer, born Hector Nazario."Letters going in front of letters, coming back through a letter, behind a letter, going across a letter... the subways became our playground," adds Riff170.

　　New York in 1974 was a city in crisis. The Mayor, Abe Beame, slashed the city's budget in a bid to stave off bankruptcy(破产), which meant laying off school teachers, police officers and subway staff.

　　"They were taking the money from the schools, there was a lot of corruption here, in this community, and so they took the after-school programmes away, and there was no outlets for this. So the outlet became our city," says Bronx-born designer Eric Orr.

　　"It was like an explosion. The graffiti explosion. All of a sudden it took over the whole city. I don't know what happened, but overnight in the early 70s it was from no graffiti to all graffiti," says another former artist, Flint Gennari.

　　Eric Felisbret, author and former graffiti artist, says graffiti culture was in a way a product of the civil rights movement. "It was never political," he says, "but many people were brought up with that, and to express yourself by breaking the law became a natural process for them."

　　The graffiti pioneers came from all races, however. "There were writers that were African American, Latino - Puerto Rico, Dominican, Cuban - Jewish, Asian, and it became one unit - one family," says another graffiti pioneer, Roberto Gualtieri.

　　Prof Gregory Snyder, sociologist and author of Graffiti Lives, says: "For lots of people, graffiti is ugly, vandalistic, and I'm not denying that. It's vandalism... now, oftentimes it's very clever vandalism. It can be written on a dumpster, like a garbage bin, and if someone's attempting to make a garbage bin look a little prettier maybe that's not the worst thing in the world."Although Mailer was not alone in welcoming the flowering of creativity, the authorities hated it, as did many passengers.

　　So when Mayor Ed Koch took office, he was determined to clean up the city and set about targeting graffiti.

　　"I remember in 1982 he brought everyone out to a train yard and there was a single train painted white," says former New York Daily News reporter Salvatore Arena. Trains were taken out of service and cleaned as soon as graffiti was spotted. Carriages were protected at night and the city agreed to ban the sale of spray cans.

If in 1984 80% of subway carriages contained graffiti by May 1989 the network was graffiti-free. "Graffiti has gone through an evolution, and it will continue to evolve. It's now socially accepted in places where 20-30 years ago that would have been impossible. It's now showcased(展示)in certain museums -and let's say in another 30 years from