LANZHOU, March 25 (Xinhua) -- In an effort to better protect ancient relics remotely located in deep mountains and forests, experts are turning to drones for assistance.

The Maijishan grottoes, over 1,600 years old, are carved in the caves of an isolated mountain peak on the ancient Silk Road in the city of Tianshui, northwest China's Gansu Province.

The 221 caves are connected by trestle roads suspended above the ground.

The grottoes are well-preserved, given their long history, thanks to the unique geological conditions. However, their location also poses challenges for the protection of the site.

To accurately assess the conditions of the grottoes, researchers have been using drones to monitor the site since 2018.

"Compared to traditional manual work, drones have a broader view and higher precision," said Hu Junjian, director of the monitoring center of Maijishan grottoes art research institute.

With the help of drones, researchers can better understand landform changes and the construction of nearby villages in a timely manner, allowing authorities to stop destructive activities or adopt protective measures accordingly.

In the summer of 2018, cultural workers discovered a rain-triggered landslide with drones.

"Without the drones, we would never have been able to discover such a natural disaster," said Xu Bokai, an official with the institute's protection research office.

After further evaluation and analysis, researchers decided that the landslide would not damage the grottoes or affect tourists, he said.

Drones have been widely used by the country in the protection of cultural relics.

Cultural workers in the provinces of Shaanxi and Shanxi have been using drones to monitor the Great Wall. Henan Province said at the end of last year that it will use drones to patrol 35 cultural relic sites.