A constructor works at the construction site of China's first tunnel across the Yellow River in Jinan, east China's Shandong Province, July 29, 2020. Located in Jinan, the 15.76-meter-diameter tunnel is the country's widest shield tunnel for both rail and road transport. With a total length of 4.76 km, the tunnel contains two levels. A two-way six-lane highway is on the upper level and the lower level is reserved for rail transit, flues and escape channels. (Xinhua/Wang Kai)