"Its ceiling is peeling off in chunks, which poses a significant threat to the stability of the roof," Chen says, adding that some parts are now barely a meter thick.

In 2018, under the approval of the National Cultural Heritage Administration, a preliminary engineering survey of the cave was conducted.

"There's a lot we need to know about it, the most complicated issue being its stability," Chen says.

Other factors range from the extent of the roof's erosion due to water and the condition of the surrounding rock, to ways to reinforce the cave, she explains.

Over the years, Chen has gone from one cave temple to another, taking care of the 50,000-odd statues and images carved into the cliffs that have been placed under her protection, particularly in the Beishan, Baoding, Nanshan, Shimen and Shizuan mountains elsewhere in the district.

Chen came to work at the Dazu Rock Carvings Museum as a cultural heritage monitor and guide in 1995.

As she showed visitors around, she became painfully aware of the threat the passage of time posed to these once beautiful stone carvings.

With a technical school background in material analysis and chemistry, she decided to join the protection center at the Academy of Dazu Rock Carvings.

She wanted to add her own efforts to protecting the sculptures, but it was only after getting involved that she realized it would not be easy.

Restoring the cultural heritage requires a certain level of historical, archaeological, metallurgical and chemical knowledge, as well as practical skills, like stone carving, casting and painting.