The 492-meter-high, 101-story Shanghai World Financial Center in Pudong district, Shanghai, is the tallest building on the Chinese mainland. The more than 30 exterior crews that clean the landmark have earned the title of "high-rise supermen" as they risk their lives to work hard every day on more than 10,000 glass curtain walls. To join the ranks, applicants to become high-rise cleaners are required to have vocational certificates and be free from high blood pressure. Of course, those with a fear of heights need not apply. Crewmembers are prohibited from wearing watches or carrying mobile phones while working high above the ground and they must stop working if winds reach Force 4 on the Beaufort scale, defined as a "moderate breeze" of 20 to 28 kilometers an hour.

On a platform outside the 101st floor of the Shanghai World Center, Chen Jianwen (left) and Tang Jin'gui check equipment before cleaning windows on March 26. [Photo/China Daily]

Yang Bo cleans the 94th floor glass curtain. [Photo/China Daily]