The Forbidden City was the imperial palace of the Ming and Qing dynasties in China, commonly known as the Forbidden City. It is named because the palace wall uses a special purple pigment for color matching, which is located in the Great Inner Forbidden. Recently, many people say that under the main hall of the Forbidden City, the floor tiles are layer after layer, and a total of fifteen floors are paved. The purpose of this was to prevent Zhu Di from digging tunnels and sneaking into the palace to carry out assassinations, and after the matter was completed, Zhu Di also killed all the insiders.

But immediately some people jumped out to refute it, because Zhu Di's first ten years on the throne were in Nanjing, and he did not think that he would live in the Forbidden City for the rest of his life, how could he hollow out his mind to do such a lack of morality? So, what is the truth of the matter?
The Forbidden City in Beijing, which was built in 1406 AD, that is, the fourth year of Ming Yongle, was built by Zhu Di on the site of the Yuan Dadu Palace. In April 2016, a construction team was working on the repair of the palace's surface west of the Longzong Gate of the Forbidden City, and the construction team inadvertently dug up the ruins of the former imperial palace. A large number of royal porcelain fragments spanning the Yuan, Ming and Qing dynasties have been unearthed.
These broken fragments, unburned by the flames of war, do not look like they have been smashed by people after a change of dynasty. According to the experts, these exquisite ancient porcelain fragments are actually because when it was complete, there were some flaws and were deliberately broken by the palace stewards. Because it was once a royal object, it must be destroyed without use, and then buried in the same place.
The ruins of the palace excavated this time are located in the southwest of the Forbidden City. Its soil constitutes the three generational distinct layers of the Yuan, Ming and Qing dynasties, so it is named "Triacle". This soil layer, in an intuitive way, pulls together the foundations of the Yuan Dynasty palace, the Ming Dynasty porcelain and the drainage structure of the middle Qing Dynasty. Since this is the first time that the archaeology of the Forbidden City has found the ruins of the Yuan Dynasty, the news is overwhelming. The legend of the fifteenth or eighteenth floor tiles of the forbidden "Taihe Hall" is probably developed from this.
However, it is more embarrassing that at the beginning of the founding of the Ming Dynasty, it was set in Nanjing, not Beijing. Later, because some ministers wrote to say that "Beiping" was "the land of Longxing", Zhu Di spent more than ten years building a palace in Beijing. At that time, the purpose of building the capital was only to use it as a foil for fengyang in the capital of Anhui, and to accompany the palace of the Northern Expedition to Mongolia, and Beiping was renamed Beijing.
It was not until the fourteenth year of Yongle (1416) that Cheng Zu consulted with the ministers and simply moved the administrative organs of the Ming Dynasty to Beijing. At the beginning of the construction of the Forbidden City, Ming Chengzu did not think that the monarchs of the second half of his life, and even the monarchs of the next five hundred years of the Ming Dynasty, would have to use the Forbidden City in Beijing as the main place of life, so it is unlikely that he would deliberately order the craftsmen to create fifteen floor tiles.
Ten years later, when Zhu Di moved the capital to Beijing, it did not mean much to lay floor tiles at this time, because there were Jinshui Rivers around the Forbidden City. The Jinshui River curves and bends, and the arch guards the heavily fortified royal palace. Digging tunnels outside the palace, the first problem to be faced is flooding. Then seeing this, some people will say that the palace was designed and built by craftsmen, and if the person who mastered the construction drawings was not killed by Zhu Bao, he would know from which direction to start digging, avoid the Jinshui River, and even dig into the Forbidden City.
However, the Forbidden City covers an area of 720,000 square meters and is the size of more than 1,700 basketball courts. What is this concept? The Tomb of the Qin Emperor covers an area of more than 520,000 square meters, and Xiang Yu wanted to dig the tomb of Qin Shi Huang, but he could not find the door for several months. Therefore, even if people found the designer of the Forbidden City himself, evaded the nine gate guards, dug through the Jinshui River and Tiananmen, when ancient science and technology were not developed, it was impossible to accurately find the positioning of the Taihe Hall underground.
However, it is worth mentioning that Zhu Di was indeed a very cruel and eccentric person in the "History of Ming" record. In ancient times, craftsmen built palaces for the emperor, and the pit killing after the end of the mausoleum also happened. Therefore, when building the Forbidden City, Zhu Di had a rule, that is, every craftsman must engrave his name on the floor tiles he fired. In this way, once there is a problem with the floor tiles, he can accurately find the responsible craftsmen and cut off their heads. Therefore, it is very likely that some craftsmen were killed by Zhu Di! In this regard, experts can only say that Zhu Di is really a cruel person!