The Forbidden Citywas initially built from 1406, the fourth year of Emperor Yongle’s reign, to 1420, the 18th year of Emperor Yongle’s reign. The project was proposed by Emperor Yongle and was built referring to the Forbidden City in Nanjing, China, where the emperor’s father finally settled the capital of the Ming Dynasty, and based on the palaces left by the Yuan Dynasty.

It covers an area of 720,000 square meters (961 meters long and 754 meters wide) and has 1,550,000 square meters of construction area, designed by Kuai Xiang (蒯 [kuǎi] 祥), who had a pen name called Ting Rui (廷瑞), was born in Suzhou, China and lived from 1397 - 1481. To build the Forbidden City, the government expropriated 1,000,000 civilians, who finally built 9999.5 rooms in 14 years. In fact, according to the on-the-spot measurement of experts in 1973, it had over 90 yards of all sizes and 980 buildings, all of which included 8707 room spaces (These room spaces include the spaces formed by four pillars which usually support a house). Finally, it is confirmed that there are 8703 rooms inside the Forbidden City.

The main buildings of it include Taihe Palace, Baohe Palace, and Zhonghe Palace (where the current emperor testes those who have passed Keju (科举), usually the only way to become government officials for average civilians in ancient China, and are qualified to participate in Dianshi (殿试), literally meaning Palace Test by the emperor).

Source: baike.baidu.com