Liu Keming, Peking Opera trouper, teaches his students in class at Northwestern Polytechnical University in Xi'an, capital of northwest China's Shaanxi Province, June 5, 2018. The university started running courses of Peking Opera in September last year to promote traditional opera among students. Peking Opera, listed by UNESCO as an intangible cultural heritage, is the most famous among hundreds of forms of local opera in China. (Xinhua/Shao Rui)