Dayan Pagoda Underground Palace is located on the west side of Dacien Temple. It covers an area of 3600 square meters. The passageways on both sides are 1500 meters long and 2 meters deep. In the evening, there are not many visitors to the underground palace, which is quiet. When you enter the underground palace, you feel the cool wind, which is quite adventurous. On both sides of the passage, there are giant frescoes of national treasure, Silk Road Style and Sanqin Range Rover. The murals are colourful and the figures are vivid. In the underground palace, there are also exhibitions of Master Xuanzang of the Tang Dynasty going west to India to collect Buddhist sutras, including in-kind exhibitions, Xuanzang's Taoist robes and worn-out cloth shoes, as well as Zen wands, golden silk robes, candlesticks, scriptures and so on. It's interesting to visit the underground palace and learn about the thoughts and customs of the Tang Dynasty and the history of Xuanzang's taking Buddhist sutras from the Western Heaven. In particular, it is worth mentioning that the red wall south of the underground palace is a good place to take pictures at night.