The first-line sky of Mount Emei, also known as Baiyun Gorge, is located under Niuxin Mountain, from Qingyin Pavilion to the first-line sky, along the west of Heilongjiang, the mountain path is winding on both sides of the river, and it is very deep in the "mountain heavy water and doubtless road". There is a canyon, the name Baiyun Gorge, the outside of the Gorge is open and clear, and the inside of the Gorge is dangerous and cool. The temperature difference between the inside and outside the gorge is large and feels strong. Enter the canyon and look up. The cliffs on both sides are obliquely inserted into the clouds. Through the dense vines and branches and leaf tip, the blue sky is exposed. It is more than 200 meters high and about 6 meters wide. The narrowest place is only 3 meters. It is only for two people to pass sideways. This scene is "first-line sky".