Title: List of planned cities
Content: The forbidden City: Built to house the emperors during Ming dynasty ; Tekes County, Ili Kazakh Autonomous Prefecture 
Title: History of the Forbidden City
Content:  City. The Forbidden City's plan was designed by many architects and designers, and then it was examined by the Emperor's Ministry of Work. The chief architects and engineers include Cai Xin, Nguyen An, a Vietnamese eunuch (unverified information), Kuai Xiang, Lu Xiang and others. Construction lasted 14 years and employed the work of 100,000 skilled artisans and up to a million labourers. The pillars of the most important halls were made of whole logs of precious Phoebe zhennan wood found in the jungles of south-western China. Such a feat was not to be repeated in subsequent years — the great 
Title: Forbidden City
Content:   When Hongwu Emperor's son Zhu Di became the Yongle Emperor, he moved the capital from Nanjing to Beijing, and construction began in 1406 on what would become the Forbidden City. Construction lasted 14 years and required more than a million workers. Material used include whole logs of precious Phoebe zhennan wood found in the jungles of south-western China, and large blocks of marble from quarries near Beijing. The floors of major halls were paved with "golden bricks", specially baked paving bricks from Suzhou. From 1420 to 1644, the Forbidden City was the seat of the Ming dynasty. In April 1644, it was captured by rebel forces led by Li Zicheng, 
Title: 1406
Content: Construction of the Forbidden City begins in Beijing during the Chinese Ming Dynasty. ; Pisa is subjugated by Florence. 
Title: Forbidden City
Content:  the vicinity of the Forbidden City, throughout the past century uncontrolled and sometimes politically motivated demolition and reconstruction has changed the character of the areas surrounding the Forbidden City. Since 2000, the Beijing municipal government has worked to evict governmental and military institutions occupying some historical buildings, and has established a park around the remaining parts of the Imperial City wall. In 2004, an ordinance relating to building height and planning restriction was renewed to establish the Imperial City area and the northern city area as a buffer zone for the Forbidden City. In 2005, the Imperial City and Beihai (as an extension item to the Summer Palace) were included in the shortlist for the next World Heritage Site in Beijing.
Title: Beijing city fortifications
Content:  in 1550, one idea called for nine small minor cities to be built around the nine Inner city gates, which would have been a formidable addition to the city defenses. Construction began in 1550 on three of these minor cities. However, because of the proximity to the Inner city gates, where many commoner's houses and shops had sprung up, many buildings needed to be dismantled. The disgruntled commoners forced the abandonment of the project not long after construction began. In 1553, it was decided that the remaining rammed earth walls of the Yuan city of Dadu would be dismantled and the raw materials used to complete the Outer city walls to form 
Title: History of the Forbidden City
Content:   The site of the Forbidden City was situated on the Imperial city during the Mongol Yuan Dynasty. After the collapse of the Yuan Dynasty, the Hongwu Emperor of the Ming Dynasty moved the capital from Beijing in the north to Nanjing in the south, and in 1369 ordered that the Yuan palaces be razed. His son Zhu Di was created Prince of Yan with his seat in Beijing. In 1402, Zhu Di usurped the throne and became the Yongle Emperor. He made Beijing a secondary capital of the Ming empire, and construction began in 1406 of what would become the 
Title: Beijing city fortifications
Content:    Beijing's Palace city or "Forbidden city" (so called because the majority of the populace was forbidden to enter) was completed in 1415. Its surrounding walls had a perimeter of 3.4 kilometres, a height of 10 metres, a thickness of 8.62 metres at the base, and a top thickness of 6.66 metres. The wall had two rows of roof tiles glazed in the imperial yellow colour set on a triangular base 0.84 metres tall. The interior and exterior sides of the walls were reinforced with 2-metre-thick bricks surrounding stones and rammed earth. The Forbidden city had four corner guard towers built in a combination multi-eaved Xieshanding style. 
Title: Beijing city fortifications
Content:  were built first to add extra defenses for the bustling commercial district south of the Inner city gate at Zhengyangmen. The eastern and western walls were planned for the second segment of the project. However, due to successive invasions from the Mongols and Manchus, soldiers were called away to the northern frontiers to defend the Great Wall, and thus few could be spared for construction. A great section of the Forbidden city caught fire in 1557, and workers and funding were funnelled towards repairs and reconstruction of the palaces. The expansion of the Outer city walls was thus never completed. In 1564, the barbicans of the Outer city gates were built.
Title: Imperial City, Beijing
Content:  were occupied by units of the People's Liberation Army. Some of these buildings remain occupied and are in severe disrepair. In recent decade, the Beijing municipal government has restored several of these temples, and established a park around the remaining sections of the Imperial City wall. Plans were drawn up to gradually move out institutions occupying various historical buildings. In 2004, a 1984 ordinance relating to building height and planning restriction was renewed to establish the Imperial City area and the northern city area as a buffer zone for the Forbidden City. In 2005, a proposal was released to include the Imperial City and Beihai as extension items to the Forbidden City as a World Heritage Site.

Question: who ordered the forbidden city to be built?
Answer: Zhu Di.