After nine years of repair work, three units of the Yungang Grottoes in Datong, Shanxi province, reopened to the public on July 10. [Photo provided to chinadaily.com.cn]

After nine years of repair work, three units of the Yungang Grottoes in Datong, Shanxi province, reopened to the public on July 10, the Yungang Grottoes Research Institute said.

In June 2012, grottoes 11 to 13 were closed for eaves construction, painting and reinforcement of dangerous rock. The project was completed last month, and opened to visitors on a trial basis.

The grottoes are a world cultural heritage site with a history that goes back more than 1,500 years.

Grotto 12 is famous for its 47 sculptures of musical instruments, including examples from ancient China and foreign lands, which shows the deep integration of the music and dance arts of various ethnic groups in past societies.