Introduction to Dajian Mountain: The mountain where Jianmen Pass is located is called Dajian Mountain. The steep stone walls on both sides of Dajian Mountain stretch for hundreds of miles, forming a natural city wall. It suddenly breaks off at the pass, leaving a long and narrow wall. The pass has two towering cliffs, like a knife and axe. This pass has become the only way to enter Sichuan and is known as the "Xiong Pass in the World".