Introduction to Neiming Pond: Neiming Pond is a perfect circle with a diameter of 33 meters and a depth of 4 meters. It is made of copper and has a copper bottom. It not only reduces the water level in the underground Xuan Palace, but also plays a fire-fighting function. If Shinto is a dry dragon, then the Jiuqu River is a water dragon. The intersection of the two dragons forms a pattern of two dragons playing with pearls, which meets the requirements of ancient Feng Shui for the harmony of yin and yang.