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 now it may be hanging in the White House,” says Nicer.

    Nowadays painted graffiti is largely gone from the New York subway trains themselves and is seen instead on the walls and tunnels of the city. It has been replaced by scratchiti(刮擦艺术) created onto carriage windows using keys, knives. Unlike the vivid images of 40 years ago, these ghostly patterns are somehow easy to ignore. After all, graffiti has faded quietly into the background.

    Smart Kids is a collection of one hundred events scheduled in October. This year, it is experimenting with Pay What You Decide (PWYD). That is, you can decide to pay what you want to or can afford, after you have attended an event. You can pre-book events without paying for a ticket in advance. Here are some of the director's picks.

    Walk on the Wild Side

    Not ticketed, Free

Join storyteller Sarah Law to hear science stories about animals. Along the way you'll meet all sorts of beautiful creatures and discover life cycles and food chains. Best suited to children aged 5-9. Children under 8 must be accompanied by an adult.

    Introduction to Waves

    Pre-book, PWYD

    Subjects range from sound waves to gravity waves, and from waves of light to crashing waves on the ocean. Mike Goldsmith explores the fundamental features shared by all waves in the natural world.

Science in the Field

    Not ticketed, Free

This storytelling night features a scientist sharing his favourite memories of gathering first-hand data on various field trips. Come along for inspiring and informative stories straight from the scientist's mouth. Join Mark Samuels to find out more in this fun-filled workshop.

    Festival Dinner

Pre-book, £25 per person

Whether you want to explore more about food, or just fancy a talk over a meal, join us to mark the first science festival in London. Which foods should you eat to trick your brain into thinking that you are full? Find out more from Tom Crawford.

    One of the most outspoken supporters that I know of women and girls is actually a man. As co­founder of the ONE Campaign, my friend Bono spends a lot of time speaking out against global poverty (贫困). Together, we're working to get out a simple, powerful message: poverty is sexist.

    Women and girls are more likely to be in poverty, less likely to get an education and more likely to suffer bad health. And when they are born into poverty, it is much more difficult for them to lift themselves and their families out of it.

    Why? One reason is that breaking out of poverty takes time­and that is a resource women around the world are short on. On average, women spend about twice as much time as men in doing the unpaid work that makes life possible for everyone, like cooking, washing, cleaning, shopping and caring. In developing countries, the gap is even much bigger. As a result, women have no time to finish their education, learn new skills, open a business, develop personal relationships or even go to the doctor. They dream of creating a better future for their children, but they can not spare the hours to put those dreams that they have into action.

    The fact that the potential of so many women and girls is going unrealized is a sad thing­but it is also an opportunity for us. We need to recognize, reduce and redistribute the burden of work that is holding them back. Because if women have time to invest (投资) in themselves and their ideas, they could transform the world.

    A while back I caught a news report on something called -couch surfing‖ and the network of trusting souls who make this phenomenon possible. They offer to put up travelers free of charge and help them on their ways. At first, it sounded unbelievable. I mean, inviting strangers into one's home for one or two nights? Give me a break.

    However, I was intrigued. I decided to investigate. The only way to truly learn about this phenomenon was to dive in. So I planned a trip to Finland, a country I've always wanted to explore. I would couch surf at every stop there.

    If ever any anxiety existed when stepping into the unknown, it disappeared when my first host met me at the train station. Ari looked like my idea of a typical Finn: tall and blue-eyed. Finns were also supposed to be famously reserved (寡言少语的). Ari was anything but. He was a live wire, giving me an enthusiastic welcome and hiking with me to his apartment, where he showed me the sleeper sofa, served me tea, and engaged me in warm conversations. He also handed me a key to come and go as I pleased.

    If this was what couch surfing was all about－trust and friendship－then I had gotten off to a good start. As I boarded my next train to continue my journey, I began to think about this couch-surfing idea. What urged these people to open their homes to strangers? I concluded that there was a desire to lend a hand to like-minded folks who might enrich their own lives.

    Seven cities in 14 days. Seven hosts. Seven new friends. If couch surfing taught me anything, it's this: Most people are good and generous. Where will couch surfing take me next? Who knows? But I can't wait to find out.

    Yinqixing Indoor Skiing Site, formerly known as Hokkaido Indoor Ski Resort, is the first indoor skiing site in Asia, which covers an area of 100.8 thousand square meters and the ski track is 380 meters in length and 80 meters in width, with the maximum drop of 42 meters. There are three sections of snow runs and a huge platform for practicing, which are suitable for skiing enthusiasts of various skiing degrees. The temperature in the skiing site maintains below -2℃ all the year round. Snow thickness ranges from 30 cm to 50 cm.

    Solo Adventure Tips:

    Location: No, 1835, Qishen Road, Qibao Town, Shanghai

    How to Get There?

    Public Bus: 91,92,803,953

    Free Scheduled Bus:

    Location: North Square, Xinzhuang Station, Subway Line I

    Departure time: from 9:00 to 21:00, operating every half an hour

    Ticket Price:

    Adults: ¥138; Children: ¥80 (Ordinary time)

    Adults: ¥158; Children: ¥100 (On weekends)

    Opening Hours:

    9: 30 to 22: 30 from Monday to Thursday and Sunday; 9:30 to 24:00 on Friday and Saturday;

    It will stop selling tickets after 21:00.

    More Tips:

    Bathing fees: ¥6 per person

    Stay overnight: ¥20 per person

    Private room of 2 people: ¥58 per person

    Private room of 3 people: ¥68 per person

    Meal: ¥50 per person

    For more information, you can click here Yinqixing Indoor Skiing Site or directly call 021-64788666/021-63816698.

Emilia Dobek traces her interest in space and the universe back to third grade when she and her father watched a blood moon — a total lunar eclipse (月食) — on the roof of their house.

Now a seventh grader at East Prairie Elementary School, Dobek recently won the national Discovery Education Lockheed Martin Beyond Challenge by designing a space station for travelling to Mars.

She says that night watching the lunar eclipse started a strong desire in her that has yet to run out of fuel. So when her teacher Andrea Smeeton received information about the national challenge, Smeeton said she immediately had one student in mind.

"I knew she would love the challenge and that she would go way beyond in her search," Smeeton said. "She immediately started researching bone density (密度) of astronauts and how to have food on Mars. "

"My design will ensure the safety of the astronauts and make sure their comfort is out of this world," Dobek says.

Dobek's design calls for building the MSS or Mars Storage Station to put the supplies in. It also includes the SGF or Self-Growing Farm, and she details how it would work with the elements on Mars.

Then there is physical and leisure activity for the astronauts under Dobek's design. A simulator (模拟装置) allows astronauts to choose their exercise machine and virtual reality environment. Rooms have circular ceilings so astronauts will be able to watch downloaded shows and even see places on Earth, such as their homes.

"I want to tell other kids to follow their passions," Dobek said. "Whatever they want to do, they should push for it and always try their best."