LANZHOU, Aug. 25 (Xinhua) -- With a single tap on a smartphone screen, celestial maidens holding lotuses, painted 1,400 years ago, spring to life and glide toward viewers from the ancient murals. At the millennia-old Mogao Grottoes in Dunhuang, northwest China's Gansu Province, cutting-edge digital immersion is doing more than offering global audiences an unprecedented journey back in time. It is also helping ens