The Jiayu Pass stands in the southwest section of the city of Jiayuguan in Gansu Province. The snow-covered Qilian Mountains run south for hundreds of miles, and the Dragon's Head (Longshou) and Horse's Mane (Mazong) mountains rise up to its north. The walls on both sides of the pass extend across the desert to join the mountains. The existing building was constructed in 1372, with two layers of walls dividing it into outer and inner sections. The outer wall was made of mud, except for its western section which was built with bricks. The double walls indicate the important strategic position of this pass.[China.org.cn/Photo by Han Bo]