Turret is situated in the Palace Museum in Beijing. The four corners of the Forbidden City seem to be normal, but in fact carry the super-high skills of ancient Chinese traditional wooden buildings. The internal structure is composed of nine beams, 18 pillars and 72 ridges. In addition to its decorative role, It, together with the city wall, city gate tower and moat, belongs to the imperial palace defense facilities, functions as watchtower, condescending, easy to detect enemy situations.