8:30 p.m., Beijing time, on the Bayi Square of Nanchang, capital city of China's southern Jiangxi province, the soaring flurescent kites lit up the dark skyline while other decorative lights went off during the "Earth Hour."

"The Earth Hour campaign gives us an opportunity to see the true color of the sky. The flurescent kites turn ever more shining against the pitch-black sky," said Huang Zhengrong, a citizen on the square.

The "Earth Hour," initiated by the World Wild Fund for Nature (WWF) in 2007, calls on families and buildings to turn off the lights for one hour on the last Saturday night of March.

China has for the second year joined the annual global environment campaign.

Latest figures show that 33 Chinese cities took part in the event along with more than 4,000 cities across the world.

In Beijing, the Forbidden City went dark for the "Earth Hour" for the first time, together with other world-famous landmarks like the Eiffel Tower in Paris and the Empire State Building in New York.

Joined the ancient royal palace are the modern architectural marvels, the Bird Nest and the Water Cubic, both Olympic venues. It's the second time for the Bird Nest to go dark for the Earth Hour.

Hundreds of people hold out glowing sticks to form a head-down arrow and the English letters "CO2", voicing their call to reduce carbon-dioxide. They are netizens from the club.sohu.com, who gathered here on a voluntary basis.

One participant surnamed Sun said: "We were strangers, but we became friends by joining this campaign. I think it's quite meaningful."

In Xi'an, capital of northwestern Shaanxi Province, volunteers gathered Saturday night to promote low-carbon activities in the north square of the Giant Wild Goose Pagoda, the city's 1400-year-old landmark Buddhist pagoda which went dark during the "Earth Hour."

In eastern Nanjing City, more than 400 buildings have taken part in the event, according to Liu Guoqiang, a local official in charge of city lighting.

"This time's event must be of larger scale than last year. Through these efforts, we hope every family could understand that now we've entered an era of low-carbon economy," said Liu.

"If we can use environmental-friendly products and turn off appliances which are not in use, it will create enormous benefits," Liu added.

The buildings might be silent and still, but people have their own ways to spend the one dark hour of Saturday than merely turning off switches.

On the web page of a week-long poll on how to spend the 60 minutes when cities go dark, thousands of Chinese netizens contributed their own ideas. Many said they would go for a walk with friends and family and have a nice talk under the night sky free from floodlight pollution.

"I'll tell my daughter the stories about my childhood when I read books and did handiwork in the candle light. I'll tell her about the fish swimming in the creek near our house and that we could drink from any springs we found," wrote a netizen named Jin Yuxia.

In eastern Hangzhou, a one-hour "dark party" was held to go with the campaign near the Leifeng Pagoda, the city's iconic tourist attraction located south of the West Lake.

"The reason for us to hold this activity is to tell people that without electricity, we can still enjoy life," Yang Dongwen, an official with the site's management department, told Xinhua.

About 80 students took part in the unplugged party, playing Hulusi (a free-reed wind instrument) and joining ethnic bamboo pole dance.