SHANGHAI - Black and white half-body portrait paintings of forty-two children line the front of the French Pavilion at the Shanghai World Expo. The children show a variety of expressions -- smiling, crying, frowning... -- and are dressed in simple clothes.

"Children of Shanghai," a work of 21 painted stainless steel panels, is an artwork by local artist Yan Peiming.

All the children's parents are migrant workers who worked on the construction of the pavilion, said Zheng Lan, a staff member of the French Pavilion.

Yan Peiming said the children, who came from the countryside to Shanghai with their families, are part of a rural exodus that has lead to the city's population explosion.

There is a need for the general public to understand the problems of urbanization in a country with 200 million migrant workers, said Yan.

Statistics show that by the end of 2009, China's urbanization rate reached 46.6 percent. It's estimated that another 400 million people from rural China will migrate to cities in the coming 20 years.

Farmers leaving their land to reestablish themselves in urban areas face numerous problems in China, such as identity issues and lack of rights compared to urban residents.

Liu Huafeng, a construction worker in Shanghai from central China's Henan Province, said his dream is just to have a good life in Shanghai.

"I hope I can bring home more money during the Spring Festival, rent an apartment to live together with my wife and son, and my son can get a university education in the future," said the man in his forties.

The Shanghai Expo, with the theme "Better City, Better Life" aims to ?make people think how to improve city life for everyone, including migrant workers and their children.

In many pavilions, including those belonging to Switzerland, Taiwan, Ningbo and Shenzhen, visitors can see life in the countryside.

Experts at a forum titled "Interaction between Urban and Rural Areas" ?held at the Expo in September, agreed more efforts were needed to reduce the gap between urban and rural areas. They said biased policies and attitudes towards migrant workers must change.

"The Expo provides an opportunity for us to learn from other countries' experiences of urbanization and find new solution to problems that occur during the process," said Sheng Yafei, secretary of Shanghai Songjiang District Committee of the Communist Party of China.

There used to be 280,000 farmers in Songjiang District, a suburb of Shanghai, now only some 5,000 still live on the fields, Sheng said.

Liu Huafeng said he only found out how wonderful urban life can be after visiting the Expo.

However, "this kind of life is too far from us. It's just a dream," he said.

The newly-concluded Fifth Plenum of the 17th Central Committee of the Communist Party of China (CPC) said the country would "universally raise people's incomes at a relatively fast pace," as one of the major targets for economic and social development in the next five years, and stressed ?"maintaining coordinated development in rural and urban regions."

The Shanghai Expo will end in a week, but the migrant children's portraits won't easily be forgotten as they symbolize an integral part of China's ever changing cities.