Lying at the center of Beijing, the Forbidden City, called Gu Gong, in Chinese, was the imperial palace during the Ming and Qing dynasties. Now known as the Palace Museum, it is to the north of Tiananmen Square. Rectangular in shape, it is the world‘s largest palace complex and covers 74 hectares. Surrounded by a six meter deep moat and a ten meter high wall are 9,999 buildings. The wall has a gate on each side. Opposite the Tiananmen Gate, to the north is the Gate of Devine Might (Shenwumen), which faces Jingshan Park. The distance between these two gates is 960 meters, while the distance between the gates in the east and west walls is 750 meters. There are unique and delicately structured towers on each of the four corners of the curtain wall. These afford views over both the palace and the city outside. The Forbidden City is divided into two parts. The southern section, or the Outer Court was where the emperor exercised his supreme power over the nation. The northern section, or the Inner Court was where he lived with his royal family. Until 1924 when the last emperor of China was driven from the Inner Court, fourteen emperors of the Ming dynasty and ten emperors of the Qing dynasty had reigned here. Having been the imperial palace for some five centuries, it houses numerous rare treasures and curiosities. Listed by UNESCO as a World Cultural Heritage Site in 1987, the Palace Museum is now one of the most popular tourist attractions world wide.
Construction of the palace complex began in 1407, the 5th year of the Yongle reign of the third emperor of the Ming dynasty. It was completed fourteen years later in 1420. 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, a suburb of Beijing. 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 the Forbidden City. 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.
Since yellow is the symbol of the royal family, it is the dominant color in the Forbidden City. Roofs are built with yellow glazed tiles; decorations in the palace are painted yellow; even the bricks on the ground are made yellow by a special process. However, there is one exception. Wenyuange, the royal library, has a black roof. The reason is that it was believed black represented water then and could extinguish fire.
Nowadays, the Forbidden City, or the Palace Museum is open to tourists from home and abroad. Splendid painted decoration on these royal architectural wonders, the grand and deluxe halls, with their surprisingly magnificent treasures will certainly satisfy "modern civilians".
明清两代皇帝居住的宫城叫做紫禁城。紫禁城有两座，一在北京，一在南京。南京紫禁城是明太祖朱元璋和建文帝朱允 4位皇帝和清代10位皇帝。他们在这里君临天下，统治中国491年，将近五个世纪。
这座故宫为什么称为紫禁城呢？原来，中国古代天文学说，根据对太空天体的长期观察，认为紫微星垣居于中天，位置永恒不变，是天帝所居。因而，把天帝所居的天宫谓之紫宫，有“紫微正中”之说。
封建皇帝自称是天帝的儿子，是真龙天子；而他们所居住的皇宫，被比喻为天上的紫宫。他们更希望自己身居紫宫，可以施政以德，四方归化，八面来朝，这到江山永固，以维护长期统治的目的。
明清两代的皇帝，出于维护他们自己的权威和尊严以及考虑自身的安全，所修建的皇宫，既富丽堂皇，又森严壁垒。这座城池，不仅宫殿重重，楼阁栉比，并围以10米多高的城墙和52米宽的护城河，而且哨岗林立，戒备森严。平民百姓不用说观赏一下楼台殿阁，就是看一看门额殿角，也是绝对不允许的。
明清皇帝及其眷属居住的皇宫，除了为他们服务的宫女、太监、侍卫之外，只有被召见的官员以及被特许的人员才能进入。这里是外人不能逾越雷池一步禁区。因此，明清两代的皇宫，既喻为紫宫，又是禁地，故旧称紫禁城。
北京紫禁城占地面积724250平方米，还没把护城河和护城河与城墙的绿化带计算在内。宫殿房屋建筑面积为155000平立米。紫禁城是一座长方形的城池，南北长961米，东西宽753米，四周有高10米多的城墙围绕，城墙的外沿周长为3428米（城墙外有宽52米的护城河，是护卫紫禁城的重要设施）。城墙四边各有一门，南为午门，北为神武门，东为东华门，西为西华门。城墙的四角有四座设计精巧的角楼。
北京紫禁城筹建于明成祖永乐(公元1404年～公元1424年)五年，兴建于永乐十五年至十八年。整个营造工程由侯爵陈圭督造，具体负责是规划师吴中。紫禁城位于都城正中，中轴线穿过皇城正中，也就是穿过紫禁城中三大殿、三大宫。紫禁城正门为正南门午门，午门是宫城中的门座，朝中大赦、献俘等重大仪式都在午门举行。其北门为神武门，东门为东华门，西门为西华门。
紫禁城作为明清两代的宫城，也分为外朝、内廷两个部分。外朝是皇帝办公的地方。举凡国家的重大活动和各种礼仪，都在外朝举行。外朝由天安门——端门——午门——太和殿——中和殿——保和殿组成的中轴线和中轴线两旁的殿阁廊庑组成。内廷是皇帝后妃生活的地方，包括中轴线上的乾清宫、交泰殿、坤宁宫、御花园和两旁的东西六宫等宫殿群组成。