Serving as imperial place during the Ming and the Qing dynasties, Beijing Forbidden City is the largest and the most complete ancient architecture complex in the world, and it was listed among the world cultural heritage sites by the UNESCO in 1987.
Initially built in the 4th year (1406) of Yongle Period during the Ming dynasty and finished in 1420, the 725,000-square meter Beijing Forbidden City measures 961 m long from north to south and 753 m wide from east to west, where 9999 rooms are available.
Beijing Forbidden City is surrounded by a 3,400-m long and 12-m tall wall encircle by a 52-m wide moat, whose architectures are all wood-structured and roofed by yellow-glazed tiles and decorated with colored paintings, sitting on greenish-white marble bases. There are four gates in Beijing Forbidden City, namely, the Meridian Gate in the south, the Godly Prowess Gate in the north, Xi Hua Gate in the west and Dong Hua Gate in the east. Mt. Jingshan, facing Godly Prowess Gate piled by soils and rocks, is studded with pines and cypresses, which serves as a protective barrier of the Forbidden City.
Beijing Forbidden City is subdivided into the outer and inner courts according to its distributions and functions, with Heavenly Purity Gate as dividing line, and the atmosphere is very distinctive from the outer court and the inner court.
Centered with Hall of Supreme Harmony, Hall of Central Harmony, Hall of Preserving Harmony, the outer court was where the emperors to hold courts and conduct grand ceremonies, and it was flanked by Wenhua Hall, Wenyuan Pavilion, Shangsi Hall and Nansansuo Hall in the east and Wuying Hall, Neiwu Hall in the west.
The inner court is centered with Palace of Heavenly Purity, Hall of Celestial Terrestrial Union and Palace of Earthly Tranquility, with the Six Western Palaces in the west, Six Eastern Palaces in the east and an imperial garden at the back, and it served as the residence for the emperors and their concubines. The Palace of Peace and Longevity situates east of the inner court, where Emperor Qianlong spend the rest of his life after abdication.