Photo taken on Dec. 18, 2020 shows the driving cab of an unmanned train on subway Line 9 in Chengdu, southwest China's Sichuan Province. Chengdu City, capital of southwest China's Sichuan Province, opened five new metro lines on Friday, bringing the number of metro lines in the city to 13. The new lines have brought the total length of Chengdu's far-reaching metro system to 558 km. (Xinhua/Liu Mengqi)
