In midsummer, the trip to Jilin in the United States-Changbai Valley Bottom Forest Sea (11), "Valley Bottom Forest", also known as the underground forest, is the lowest elevation scenic spot in the Changbai Mountain scenic area. The depth of the valley is more than 60 meters, and the width of the valley is about 3000 meters. It stretches for several kilometers. As a result of mountain-building and volcanic activities, a large area of strata collapses, forming a huge valley, and sinking the entire forest into the valley. Bottom. Nature has done a little kungfu to create this wonder of the world. Walking along the trestle road, ancient trees are towering, ancient rocks are scattered, the air is fresh and cool, forming a natural oxygen bar, which makes people happy physically and mentally; standing at the edge of the forest at the bottom of the valley, the whole forest at the bottom of the valley has a panoramic view, where rare birds and animals, rare tree species and vegetation live and grow, which can be said to be "hiding the secret of nature, containing the spirit of all ages".