Among the four Heavenly Gates in the east, west, south and north of Zijin City, only the South Heavenly Gate is accessible for entry and exit. In Chinese legends, the South Heaven Gate is the first major gate to enter the Heavenly Palace and also the main entrance to the imperial palace, solemn and sacred. At the South Heavenly Gate of Zijin City, there are three gate openings, namely the Divine Gate, the Ghost Gate and the Human Gate. The Ghost Gate is a symbolic gate that has been closed since its construction. The Divine Gate, on the other hand, remains closed all year round. There is no record in historical materials that it has ever been opened. Only the adjacent human gate is available for people to walk on. Entering the South Heaven Gate, along the edge of the Zijin City Wall, there is a steep footpath that leads directly to the Lingguan Hall. Here, one can truly feel the shock that the city walls of Zijin City bring to people. The city wall, with each huge stone slab weighing a thousand jin, is built along the direction of the cliff. Due to the use of a tapering technique, it creates a special effect where the wall "slopes outward when viewed from the inside and inward when viewed from the outside". Someone measured that the foundation of the city wall is 2.4 meters thick and the top is 1.26 meters thick. Its weightiness and firmness fully reflect the imperial edict of Emperor Yongle Zhu Di of the Ming Dynasty: "..." It must be solid and strong, and last for ten thousand years as long as heaven and earth.