青藏铁路 (Qīng-Zàng Tiĕlù), the Qīnghăi-Tibet Railway, also known as the Sky Road, is the world’s highest-altitude railway line (highest point is 16,640 feet above sea level).
In his book, “Sailing through China” (1984), travel writer and novelist Paul Edward Theroux wrote that “the formidable Kunlun Mountain range [...] guarantees that a train to Lhasa will never be built”. Now it’s there.
Stretching from Xīníng in the East to Lhasa in the West, it’s an impressive piece of engineering. The railway was massively difficult and dangerous to build due to the perennial ice and slush, extremely low temperatures, and fragile ecological environment of the region.
The railway was finished in 2006, and has since played an important part in the economic development of Tibet, contributing to the tripling(!) of the Tibetan GDP between 2006 and 2015.
A train car with a view. Wikimedia Commons