Sun believes they are recording their own history in this way.

He is proud about a chart they made on migrant workers' history: in 1978 China reported few migrant workers, the number increased in 1984 and soared abruptly at the end of 1990s and the early 21st century along with China's economic takeoff.

He especially mentioned the year 2003 with two milestones: Premier Wen Jiabao demanded back wages for a migrant worker and Sun Zhigang's death. "Only those who have been through the discrimination and sufferings can understand importance of the two episodes," Sun says.

In February this year, China's National People's Congress (NPC) confirmed the qualification of three rural migrant workers as newly-elected deputies, making them the first batch of "spokespersons" for migrant laborers all over the country in the top legislature. Experts hailed it as a breakthrough in the country's history, hoping it will ease the tension between the city and the countryside.

The Communist Party of China (CPC) Central Committee issued a landmark policy document on rural reform and development in October this year, vowing to enhance safeguarding the rights of migrant workers, ensuring them the same wages and benefits in term of their children's education, public health and housing as citizens.

However, there is still a long way to go. Migrant worker Yang Lihong and her daughter came to visit the museum. Her daughter was to sit the university entrance exam in two years, but she has to return to their hometown where her permanent residence was registered to sit the exam.

"It's hard for us to return," Yang says. She and her husband left their hometown 18 years ago. The farmland was taken back for they defaulted paying taxes and other fees. The home collapsed. "My daughter often asked why we are different from Beijing locals."

She could only pin hopes on "permanent residence registration" reforms, which involve balancing urban and rural resources on education, medical services and insurance among 1.3 billion Chinese. Though she dreamed about it, Yang also admitted, "It's hard to tackle the problem in a short period of time."

A poem by a migrant worker in the museum depicts the dilemma of migrant workers are in:

"Roaring machines replace chirping birds and insects/Roads filled with cars you have to watch out and strangers' faces/ Fellows from the same hometown go together to comfort each other/ Have to live humbly and carefully/ Sometimes sad about the disappearing of rural idyllic life/ However/ Hometown only exists in memory/ Hometown now/ Is as bewildering as cities migrant workers are living in."

(Xinhua News Agency November 2, 2008)