Construction of the palace complex began in 1407, the 5th year of the Yongle reign of the third emperor (Emperor Chengzu, Zhu Di) of the Ming dynasty. It was completed fourteen years later in 1420, and then the capital city was moved from Nanjing to Beijing the next year. It was said that a million workers including one hundred thousand artisans were driven into the long-term hard labor. Stone needed was quarried from Fangshan District. It was said a well was dug every fifty meters along the road in order to pour water onto the road in winter to slide huge stones on ice into the city. Huge amounts of timber and other materials were freighted from faraway provinces.
Ancient Chinese people displayed their very considerable skills in building it. Take the grand red city wall for example. It has an 8.6 meters wide base reducing to 6.66 meters wide at the top. The angular shape of the wall totally frustrates attempts to climb it. The bricks were made from white lime and glutinous rice while the cement is made from glutinous rice and egg whites. These incredible materials make the wall extraordinarily strong.