Archaeologists have made a stunning discovery of more than 80 stone carvings and building units, dating back about 1,300 years, at the Leigutai caves of the Longmen Grottoes in Luoyang, Henan province.

The Longmen Grottoes Research Institute, which oversees the UNESCO World Heritage Site, made the announcement as the Leigutai caves reopened to the public on Wednesday after renovation.

The relics, found during renovation inside the west wall of the south cave of Leigutai, which sits on the east hill of the grottoes, are believed to have been used as materials to strengthen the wall during restoration work after an earthquake struck the area in the 16th century.

"This is the first time archaeologists have found statues inside a wall at the Longmen Grottoes," Lu Wei, director of the history and humanities research center of the institute, told China Daily.

The grottoes were first built in AD 493. In the 14 centuries that followed, rulers of different dynasties and numerous pilgrims kept expanding their scale. There are currently more than 2,300 caves and niches on the steep cliffs of two hills flanking the Yihe River.

The Leigutai site, boasting three major parallel caves and dozens of smaller caves and niches, was built on the east hill during the reign of Empress Wu Zetian (690-705) of the Tang Dynasty (618-907).

In recent years, cracks surfaced on the walls and roof of the Leigu-tai south cave and falling bricks posed serious risk for visitors.

Ma Chaolong, director of the protection center at the institute, told Henan Daily in an interview that the situation worsened after heavy rains in Henan in 2021 led to water leakage. The renovation work was completed last week.

Lu, the history and humanities research center director, said that workers engaged in the project noticed a bulge on the west wall of the south cave. When they pulled down the wall, they found an array of exquisite stone statues, pottery statuettes used for decorating rooftops and bearing stones used to support doors.