The Karakorum Highway, where the bus is driving, was once a leg of the ancient Silk Road, with its foundations built by locals centuries ago.

However, it wasn't until 1978 — after nearly 20 years of construction by more than 24,000 Chinese and Pakistani workers — that it was officially inaugurated for vehicles, which brought trade, tourism and ease of travel to this remote part of the world.

Next to me on the bus sat Saif Ullah, a recent master's graduate from the Chinese Academy of Sciences. Ullah didn't stop filming the stunning glaciers outside the window. He was returning home to southern Pakistan for the first time by land.

About one and a half hours after crossing the pass, the bus reached the town of Sost.