The workers' tasks require both physical strength and technique. Their risky work on the uppermost part of the stadium is reflected by their relatively high salaries. They can earn over 3,000 yuan ($412) a month, plus meals and accommodation.

Old Di, the electrician. [China Daily]

Forty-year-old Shen is the chief of his team. He is a steady fellow, who has won the boss' trust. On most days, Shen takes along the blueprints of the stadium, weaving left and right through its steel frame to check up on work done earlier. The company has praised the top quality workmanship of Shen's skilled team, earning them the role of remedying problems arising during construction.

"The check-up work is not as easy as we imagined. Apart from technique, work safety is another concern," Li Ning says.

"Every single steel frame is no more than 1m and settled at a slightly oblique angle. The square just admits two men standing side by side. It is especially risky for the builders, who work girded to the intertwining frames by a short rope tied to one lower end of the frame."

Shen's son is another regular at the building site, though he is not on the payroll. But the foreman has little to do with his boy, who dropped out of school on account of low grades and discrimination from his peers. The boy came to Beijing with the hope of finding another school, but was thwarted by the 25,000 yuan annual tuition cost.

A worker at the National Stadium. [China Daily]

From time to time, Li and Zhu take the boy to visit Beijing's museums or Happy Valley amusement park. Li says he feels sorry for the dropout and has also given him books, hoping to enrich the boy's mind and his life.

Welder Li Anming is another skilled worker who carries great weight with his team. A former Liyang seafood seller with a tattoo of a powerful tiger on his back, Li is the breadwinner of his family of four.

Last year, he finally saved enough money to make his dream come true - to replace the dilapidated house he had first built in the 1980s. The two documentary makers visited Liyang in April to witness the tearing down of Li's old dwelling. The happy welder had built his new home by July.

"We were invited to see the new house as well," Zhu said. "And it really surprised us. The early ruins turned out to be a triplex villa with a pond that led onto the second floor via a 3m wide stairway."

But Li's wife worried about finance. The family had spent 20,000 yuan on the building, plus more on the interior, and found themselves in debt in order to complete the project.

"Well, Anming still oozed confidence for the future. He reserved a space for parking and planned to save money for buying a car," Li's wife says. "He is building the Bird's Nest that cost the government more than 3 billion yuan in Beijing. Equally, the new house upon which he has spent much labor and energy is almost done, so a slight overspending won't dampen his zeal."