Cleaners prepare to clean windows outside the 101st floor of the Shanghai World Financial Center March 26, 2012. More than 30 workers on the window-cleaning team of the skyscraper work in pairs every day. The cleaners have to obtain a license for high-rise operations and must not have high blood pressure or a fear of heights. They are not allowed items which could fall, such as cell phones or wristwatches, and must stop working in heavy winds.

Window cleaners outside the 101st floor of the Shanghai World Financial Center March 26, 2012.

Yang Bo cleans a window outside the 94th floor of the Shanghai World Financial Center March 26, 2012.