The natural plank road. The first route of the Aerial Forest Trail is named "Tianzhan Plank Road" because it is located in the deep mountain canyon of Zhashui County in Yan'an City, Shaanxi Province. The trail is built on a cliff with a high height and a quite dangerous environment. The builders of the plank road followed the terrain and built it according to the mountains. The mountains are overlapping and the trees are prosperous. Along the way, the magnificent landscape of the virgin forest and the rich ecological environment are displayed. At the same time, the natural terrain of this plank road is rugged and there is a certain degree of danger. People who like challenges like challenges. Tourists who are adventurous and adventurous are more likely to become addicted, so it is called the "naturally dangerous plank road".