A Tang Dynasty (AD 618-907) porcelain figurine unearthed in the Suoyang City ruins. Provided to China Daily
"The change is vast," says Cai Chao, executive director of the Gansu section of the Silk Road and architect at the Institute of Architectural History, a major planner for the project. "This area has always been a hot spot for experts and archaeologists. Now it has also become a place for ordinary people to look back at history."
The work started from within. In the Yumen Pass, a frontier pass leading to the north from the ancient Chinese territory, the missing parts are mended with adobe made from original material and ramming craftsmanship.
The surface of the relics is sprayed with anti-weathering material developed by the Conservation Institute of Dunhuang Academy, which has been responsible for the conservation of major sites on the Silk Road, while the cracks are filled with grouting materials.
A total of 5 million yuan ($803,000) has been invested in the monitoring system that records the temperature and humidity of the relics.
"The dry climate in the area makes it easier to preserve earthen ruins. It would have been impossible in the south," says Guo Qinglin, deputy director of the Conservation Institute of Dunhuang Academy.
To allow people to better understand the value of the relics, a large-scale renovation of the sites was launched in 2006.
Until the early 1980s, the Big Fangpan Castle in the Yumen Pass was used as a sheepfold for the local farmers, says He Guowu, head of the administration office of the Yumen Pass.
In 2012, Cai and his team started restoration work on the site. Mines near the site were shut down. Now people can follow the wooden trestle that leads into the castle, where a glass-clad platform has been built so visitors can see the interior of the castle without causing damage.