Buddhist murals have been previously found in North China's Shanxi province and the city of Dunhuang in Northwest China's Gansu province. Experts say the discovery of the Donggar and Piyang grottoes provides a missing link for historians, allowing them to fully trace the origins of Buddhism in China. The murals depict substantial contents, including exotic figures, animals, patterns and designs.

In addition to giving free lectures to tourists, Rigzin inspects the grottoes every day in case of water seepage or collapse.

In June this year, Rigzin just bid farewell to his beloved work. "I hope young people can take over the responsibility and continue to guard the grottoes,"He said.