Leading actress Shen Aojun and leading actor Guo Xiaodong are pictured on location of the documentary The Secret of Tibet in Lhasa, capital of Tibet autonomous region on Aug 28, 2011. The documentary started filming in Lhasa on Aug 20, 2011. The story, focusing on the changes of four Tibetan aristocrat families from 1935 to 1950, reveals the tragic life of a serf in old Tibet which was hardly known. [Photo/chinadaily.com.cn]