V. The lowest line: Lanzhou-Xinjiang high-speed rail goes through the Turpan Basin in Xinjiang and most part of the basin is at an altitude below 500 meters. And the Ayding Lake, close to the southern foothills of the basin, is 155 meters below the sea level. It is the lowest point in China.

(File Photo)

VI. The highest high-speed rail: Lanzhou-Xinjiang high-speed railway runs through the world's highest tunnel pass through the Qilian Mountains. The 9.49-km No. 2 tunnel connects Qinghai and Gansu provinces, with the highest altitude reaching 4,345 meters, which is the world's highest high-speed rail.

(File Photo)