Even those who have never before visited the Palace Museum have probably heard of the “Three Great Halls”, which comprises the Hall of Supreme Harmony (Taihe dian), Hall of Central Harmony (Zhonghe dian), and Hall of Preserving Harmony (Baohe dian), in the outer court and are recognized as the architectural center of the Forbidden City and the symbol of concentrated imperial power. They are the most important group of structures within the imperial palace.