A worker mixes color at the Guangling Ancient Books Printing Society in Yangzhou, east China's Jiangsu Province, Feb. 25, 2014. The technique of block printing, with a history of over 2,000 years, was listed as a state intangible cultural heritage of China in 2006. In order to better protect the technique, the Guangling Ancient Books Printing Society was founded in Yangzhou in 1958. The society has maintained the only full set of block printing technique in China. (Xinhua/Cui Genyuan)