Introduction to Happy Sky: Happy Sky was originally called "Shutan", which is the valley bottom in front of Longmen. It has a flat terrain and an open area. People follow the mountains to enter the valley, which is difficult and steep, and inevitably they are out of breath and their legs are weak. At this point, the terrain suddenly becomes gentle and you can walk freely. Visitors suddenly feel light and relaxed, so it is called "Happy Day". According to legend, the Red Eyebrow Army once camped here. On the surrounding hillsides, there are still more than ten stone mortars used for pounding rice in ancient times, as well as village gates and walls.