Twenty kilometers east of #CNPC's Yumen Oilfield, one of China's earliest developed oilfields, lies Jiayu Pass, a World Cultural Heritage site. First built in the 5th year (1372) of the Hongwu reign in the Ming Dynasty, the 60-kilometer-long pass was the western end of the Great Wall of the Ming Dynasty (1368-1644) and served as a defense system. More than 600 years later, the ancient Chinese fortress has become a famous tourist attraction. #CNPCGreenDevelopment | CNPC