Photo taken on Oct. 8, 2020 shows fresco in Arjai Grottoes in Otog Banner of Ordos, north China's Inner Mongolia Autonomous Region. Cultural heritage workers started restoring the frescoes in the 1,600-year-old Arjai Grottoes in 2018. The site has 65 grottoes. Of the 41 grottoes that have remained intact, 14 feature frescoes. Ten grottoes featuring frescoes have been restored. (Xinhua/Li Zhipeng)