A bird's-eye view of the Zhongdu site in Fengyang county, Anhui province.[Photo provided to China Daily]

The 840,000-square-meter imperial city in Zhongdu is slightly bigger than its younger cousin in Beijing. Its construction began in 1369, one year after the Ming Dynasty's founding.

Soon after Zhu Yuanzhang, who was once a poor peasant, toppled the ethnic Mongolian Yuan Dynasty (1271-1368) in China and built up his own empire, he decided to make his hometown the national capital.

An ambitious urban-infrastructure project began, and the emperor later bestowed the auspicious name Fengyang (literally, a rising sun like a flying phoenix) upon his home county.

Wu Wei, the archaeologist from the Palace Museum in charge of the excavation, says a much larger outer city was then planned around the palatial section.

Archaeological investigation shows the city could cover 50 square kilometers, including military facilities, temples, mausoleums and nobles' residential areas in addition to the palatial compound.

"Zhongdu plays a crucial role in the history of China's urban development," Wu tells China Daily.

"It inherited elements and mentalities from previous dynasties. And its layout, in particular, contributed to the later period. It drew a blueprint for the Forbidden City."

According to Ming Shilu (The Veritable Records of the Ming)-the comprehensive imperial annuals written by historians during the dynasty-a map of the imperial city of the Yuan Dynasty in Beijing (known during the Yuan Dynasty as Dadu, or Khanbaliq) was offered as a tribute to Zhu Yuanzhang in 1369 as a reference to construct his own capital.

"From the design locating palaces along the city's axis to the three-layer structure-the outer walled city, the forbidden city and the palatial city-we can see the layout of Zhongdu was derived from Dadu," Wu explains.