Wang Qingyu introduces the skills of duplicating frescos at a museum of Balin Left Banner, Chifeng City of north China's Inner Mongolia Autonomous Region, Aug. 2, 2019. Wang Qingyu, a retired worker of a museum in Balin Left Banner, has been working for the duplicating of frescos of Liao Dynasty (916-1125 A.D.) for 40 years, and has altogether reproduced 50 plus precious frescos of Liao by far. (Xinhua/Peng Yuan)