The stone towers at Arjai Grottoes in Otog Banner in Ordos, in North China's Inner Mongolia autonomous region, on Oct 18 [Photo/Xinhua]

The project to strengthen the ancient Arjai Grottoes in Otog Banner in Ordos, in North China's Inner Mongolia autonomous region, was basically finished on Oct 22, according to local media reports.

The project to comprehensively protect the murals and rock masses of the grottoes is, however, still ongoing.

Arjai Grottoes is the largest discovered in the grassland area in the world. They are the only Buddhism grottoes left in the grassland area, to the north of the Great Wall of China. There are nearly 1,000 colored murals covering more than 2,000 square meters in the grottoes.

Academics believe the Arjai Grottoes were built 1,600 years ago. They say it is a Buddhism art treasure integrating temples, grottoes, cliff stone carvings, murals, sculptures and inscriptions.

It is also a rare set of historical material for studying ancient history, culture and customs.

In August 2018, the Otog Banner's government fully launched the protection projects for the Arjai Grottoes and entrusted the Dunhuang Academy to implement the projects.

Officials said that the entire protection project will be completed in 2021.

According to local media reports, archaeologists have discovered 65 caves and 22 enchased stone towers.

In addition to a large number of murals of religious content, the grottoes also have many precious murals with secular content.

Moreover, there are many early period Tibetan and ancient Uighur Mongolian inscriptions in the grottoes. Experts say it is the relic with the largest number of Uighur Mongolian inscriptions in the world.