What is the meaning of the tortoise-backed snake in tourist attractions?

Xuanwu is a spiritual thing composed of turtles and snakes. Xuanwu originally meant Xuanming, and the ancient sounds of Wu and Ming are interlinked. Wu means black; Ghost means yin. At first, Xuan Ming described the tortoise divination as follows: the tortoise's back is black, and the tortoise divination is to let the tortoise go to the underworld to ask his ancestors, bring back the answers and show them to the world in the form of divination. Therefore, the earliest Xuanwu is the tortoise. Since then, the meaning of Xuanming has been expanding. Turtles live in rivers, lakes and seas (including turtles), so Xuan Ming became a water god; The tortoise lives long, and Xuan Ming has become a symbol of immortality; The first underworld was in the north. In the Yin and Shang Dynasties, Oracle Bone Inscriptions divined that "divination will point to the north", so Xuan Ming became a northern god again. Xuanwu, also called "Zhenwu", commonly known as "Zhenwu Emperor", is the god worshipped by Taoism. According to legend, the prince of Gu Jing Le Wang was born fierce and traveled in the East China Sea. When he met the immortal, he gave him a sword and went to Wudang Mountain in Hubei Province to practice. After 42 years of success, it rose during the day and became the Northern Xuanwu Army of Weizhen. But in the Song Dynasty, it was renamed Zhenwu because it was forbidden to use mysterious figures. Xuanwu is also said to be a big turtle in the North Sea. This turtle was once used as a pillar to support the whole Penglai Fairy Mountain. Because of its profound spiritual awareness, after years of hearing and seeing, it finally came to fruition. Therefore, there are many tortoise-borne tablets in the imperial mausoleum, which is the secret of Xuanwu. In addition, Xuanwu is also called Xuanming, so it is also called Beiming. Hearing this name, it is estimated that many readers will associate it with Bei Ming's return to the sea and Jin Yong's "The Legend of the North Ghost" written by Xiaoyao. Xuanwu, like other three spirits, is also derived from the 28 stars on earth: bucket, ox, female, air, danger, house and wall. However, people after ancient times have the following explanations for Xuanwu. Xuanwu is a tortoise. Book of rites "Quli" in the cloud, "before the trip, Zhu bird and then Xuanwu. . "Xuanwu" is a tortoise and snake. Supplement to Hong Xingzu's Biography of Chu Ci: "Xuanwu is called tortoise and snake. Located in the north, it is called Xuan. With a scale, it is called martial arts. Xuanwu is a combination of snakes, turtles and snakes. However, Xuanwu was upgraded by later Taoist priests to the Northern Emperor-Emperor Zhenwu.