Photo taken on Dec. 25, 2018 shows the tunnel construction site of the Jiyuan-Yangcheng expressway in Taihang Mountain in Jiyuan, central China's Henan Province. The expressway, which links Jiyuan of Henan with Yangcheng of north China's Shanxi Province, will open to traffic by the end of 2019. (Xinhua/Zhu Xiang)