In Chongqing, 69 residents have volunteered to guard the ancient Dazu Rock Carvings for decades to come.

More than 50,000 individual rock carvings lie in the grottoes of Chongqing's Dazu district, dating from the 9th to 13th centuries. They were placed on the UNESCO World Heritage list in 1999.

To protect the relics from theft and vandalism, the first batch of volunteers started working in 1987. Today, they range in age from 46 to 82. They often serve alone at the site. Some families have guarded the grottoes for two generations.

Wang Xinshu, is the eldest of the sentries. The 82-year-old was recruited by the local cultural relics department in 1987 and has guarded Jianshanzi Grotto — among Dazu's most ancient — ever since.

"There was no road to the grotto deep in the mountain," he recalled. "I had to walk uphill for an hour and a half to reach the site. I think it is my destiny to protect this grotto."

Video by Li Dong and Chen Kenan