Ambitious plan

After winning a civil war in 1402, Zhu Di, the third ruler of the Ming Dynasty, who was also known as Emperor Yongle, decided to move the national capital from Nanjing, the present-day capital of Jiangsu province, to Beijing, where he lived as a prince.

It took years to collect the best materials nationwide for the new city. In 1417, a three-year huge construction effort was launched in Beijing. It is estimated that this ambitious plan involved 1 million construction workers and artisans.

However, fire proved a major adversary for the emperor and the Forbidden City, the world's largest wooden architectural complex. Just a few months after Emperor Yongle moved to his new home in Beijing, Taihe Dian, which was then called Fengtian Dian (the Hall of Venerating Heaven), and several other key palace buildings were destroyed in a raging inferno.

In the years that followed, construction in the Forbidden City often fell victim to fire-usually caused by lightning--and had to be constantly renovated or rebuilt. Many buildings in the compound were also doomed in the war of 1644, when rebels seized Beijing and toppled the Ming Dynasty.

Xu Haifeng, director of the archaeology department at the Palace Museum, said: "Although the original format was basically retained, the details changed every time a palace was reconstructed. Most buildings in the Forbidden City today are from the Qing Dynasty or the later period of the Ming Dynasty, and people always wonder what the venue looked like during its earliest days."

The size of some palace buildings also shrank over time, mainly because it became increasingly difficult to find lumber sufficiently large to use as building material.