Introduction to Jiudao Tianguan: The back mountain scenic area is so high that it looks like it is hanging into the sky. You have to go through overlapping dangerous passes to reach the top. It is known as "Nine Dao Tianguan" in history. There are Tengyun Cave and Tongtian Cave on the way. After walking through, it suddenly becomes clear, as if you have arrived at the Imperial Palace of Heaven, and you can see the strange mountains and strange scenery attached to each place.