Introduction to Xianyuan Tower: Xianyuan Tower is located in the north of Xiandu Square in Yunwai. It is a two-story building with brackets and mountain tops. It is also the gatehouse for entering and exiting the scenic spot. The plaque hanging above the gate tower is engraved with the two characters "Xianyuan", which was inscribed by Li Shimin, Emperor Taizong of the Tang Dynasty. Legend has it that when Emperor Taizong of the Tang Dynasty personally led his army to conquer Korea, he happened to encounter the wonder of mirage along the way. He was so amazed that he called it "the source of immortality".