The construction site of Shanghai Tower (L, bottom) is seen in Pudong District of Shanghai, east China, Dec. 8, 2010. The number of skyscrapers increases in several cities of China in order to save the land resources, to attract business and to improve the image of cities. But there are critics in China saying that skyscrapers cost much for the operation. Their arguments also include that skyscrapers are usually weak in case of disasters, such as earthquakes, explosions, fire accidents and so on. [Xinhua]