In pictures: "rainbow mountains" in NW China

Visitors walk at the foot of the "rainbow mountains" in Zhangye city in Gansu province on April 2. [Photo/Xinhua]

What you want to know about Zhangye city

Located in the middle of the Hexi Corridor, Zhangye city was an important commercial hub along the ancient Silk Road and a political, economic, cultural and diplomatic center of Northwest China in ancient times.

The Hexi Corridor, also called the Gansu Corridor, was part of the ancient Silk Road. During the Western Han Dynasty (206 BC-AD 24), the corridor was an important route linking North China and the Tarim Basin and Central Asia taken by traders and the military.