The filmmakers have also great admiration for Old Di, the electrician. At 65, Di is the most experienced of the three central characters. His father, who passed away in 1982, worked for the underground Party before 1949. Born into a strong military atmosphere, Di put on the soldier's uniform when he was young and was later made bodyguard of a military commissar in Beijing.

Di subsequently worked as a patrolman on Chang'an Avenue and participated in disaster relief work following the 1976 earthquake at Tangshan, Hebei province. Di was discharged from the army at 37. In 1989, he became a migrant worker.

Zhu says: "Decades of hard life endowed him with a sense of calm and disengagement. Even now, a neat and trim appearance is what he always cares about, just as he did in the army."

The two filmmakers plan to revisit the Bird's Nest for the Lunar New Year as a finale to their work. Since late 2006, they have accumulated 2,500 minutes of footage, and shot more than 200 pictures. Their own Olympic dream has almost come to fruition.

Their project has attracted the attention of Beijing Photographers' Association deputy manager, Li Yingjie. "I often meet them at the site, and every time they are climbing up onto the top and walking in the mud. But their shots focus on the common worker all along, which is quite invaluable in today's society full of careerism," Li says.