From Dunhuang to Yumenguan nearly 100 kilometers, it can be reached in 1 hour by car. From Yumenguan, along the ancient Shule River Valley, there are swamps, water lakes, meadows, water grasses, cattle and sheep in groups, and water birds such as wild ducks, egrets, big lizards, gray cranes, swans and other water birds in the water. From time to time, flocks of wild ducks and other water birds fly in the blue sky. On the way, passing through the Great Wall of Han, and other monuments, and then traveling 10 kilometers west, after arriving at the pit, the Shule Valley marsh gradually dried up, the meadow gradually disappeared, the valley was obliterated by the Gobi Desert, and continued to travel west along the valley for about an hour. Suddenly, an ancient castle like a medieval appeared in front of it. This is Yumenguan Yadan Devil City, the suburban buildings are relatively sparse, entering the city is gradually prosperous, the buildings are dense, and the scale is scaled.