Yanshan Mountains in the north of Hebei Province, China. From Badaling in the west to Shanhaiguan in the east, the altitude is mostly below 1300m. The average altitude is about 1 100 meters, and the highest peak is Duyu Mountain with an altitude of 2 1 16 meters. The Yanshan Mountains are eroded and denuded in the middle or low mountains. The mountain breaks through the longitudinal ridges and valleys. The piedmont plain is the closest, most typical and strongest warm temperate semi-humid monsoon climate zone in Beijing. It is a mountainous terrain with a large windward slope of Yanshan Mountain, which inclines to the northwest, and is the topographic height of Duolie Mountain which inclines to the southwest.
Therefore, Liwen District of Yanzhou City may be an imaginary non-existent area.