The first carvings at the Thousand-Buddha Cliff in Guangyuan, on the east bank of the Jialing River, date from the late Northern Wei Dynasty (386–534 AD). The site entered its golden age during the Tang Dynasty (618–907). Today comprising more than 7,900 statues, it is the largest grotto complex in Sichuan Province. In December 1939, celebrated architects Liang Sicheng and Liu Dunzhen conducted a survey of ancient architectural sites in the area. They discovered that the Sichuan-Shaanxi Highway, which ran beneath the cliff, was putting the ancient carvings at risk. It's as a result of their tireless campaigning that this precious cultural heritage site could be preserved.