The Site of Chang'an of the Han Dynasty (206BC-220AD) is located about five kilometers northwest of today's Xi'an city, the capital of Shaanxi Province. Chang'an city was first built during the period of the Western Han Dynasty (206BC-25AD). The ruins of this city are just separated by Longshouyuan Mountains from the ruins of another city, the capital of the Tang Dynasty (618AD-907AD), which was also named Chang'an. The Chang'an city of the Han Dynasty was very large in area with exquisite designs and layout. As a proof of the long history and deep culture of today's Xi'an city, this city had always served as the political, economic and cultural center during the two hundred years in the Western Han Dynasty. And this area nowadays is under state-level protection.
It took the ancient people more than 90 years to finish the construction of the whole city. It could be divided into three phases. At that time, inside this city there were numerous luxurious palaces, great mansions and big temples. The most famous places included Changle (it means forever happiness) Palace, Weiyang (it means that something has not ended) Palace and Jianzhang Palace. In the year 202BC, Liu Bang, the founder of the Han Dynasty, ordered to repair the original Xingle (it means thrived and happy) Palace from the Qin Dynasty (221BC-206BC), and renamed it Changle Palace. After that he began to construct his capital city as well as handle the state affairs in Changle Palace. According to historical records, Liu Bang ordered to build Changle Palace as soon as he and his army came to Chang'an city, and as a result, this palace was one of the earliest palaces in the city. Other palaces were built much later than this one, such as the Jianzhang Palace, which was constructed actually more than 80 years later during the reign of Emperor Wu (Wu means valiant), and Chang'an city was also renovated and enlarged at that period. The famous Kunming Lake, which was mentioned in the poem of Du Fu, a famous poet in the Tang Dynasty, was also constructed at Emperor Wu's reign.
In the year 199BC, the emperor decided to build Weiyang Palace on the west side of Changle Palace in order to accommodate his big royal family. This was the first phase in the construction of Chang'an city, during which some giant palaces were built.
Then in the year of 194BC, during the reign of Emperor Hui (Hui means kind), the original city walls were repaired and rebuilt. The whole project lasted more than four years and ended in September, 190BC. This was the second phase.
The third phase began much later, starting with the construction of Jianzhang Palace. In the year 104BC, when Emperor Wu ascended the throne, he ordered to build the Northern Palace, Gui Palace, Mingguang Palace, and Jianzhang Palace. In the meanwhile, Shanglin Garden and Kunming Lake were also constructed in the western part of the city, where Jianzhang Palace was located. When these projects were all finished, the whole construction and renovation of capital city came to an end. This was the last phase.
The whole Chang'an city in the Han Dynasty had a circumference of 25.7 kilometers, covering an area of 36 square meters. However, the shape of the city was not a regular rectangle. It actually looked like the shape of the Big Dipper. As a result, the city was nicknamed Big Dipper City. The streets in the city were all in quite reasonable layouts, with eight big main streets, 160 alleys and nine districts. All the streets were very flat and wide, and they were 12 times as wide as today’s railway tracks. On either side of the streets, trees were planted, including Chinese locust trees, elms, pines and cypresses, which were densely distributed and could create large shade at summer. In its golden time, the whole city had a population of over 300,000. It was regarded as one of the earliest big cities in Chinese history.
The positions of most original streets in Chang'an city of the Han Dynasty could not be fully figured out by experts at present. In the northern part of the city, there used to be nine big markets, of which one was specially used for book trade. All the markets had their own special functions, which could reflect the prosperity of the capital city.
According to the archeological materials and the results of excavations, the city walls of the Chang'an city were all constructed with yellow earth. With a height of 12 meters and width of 12 to 16 meters, the walls were protected by a three-meter-deep moat, which was as wide as 8 meters. According to excavation results, there were altogether 12 big gates and 36 smaller ones, and the two numbers were in accordance with historical records.
With the renovation and enlargement project finished under the order of Emperor Wu, there was no more construction work ever done after his reign. Between the Han and the Tang Dynasties, there were another five small kingdoms establishing their capitals here, including Former Zhao, Former Qin, Later Qin, Western Wei and Northern Zhou, which were all small kingdoms or states during the period of Northern and Southern Dynasties (420AD-581AD). In addition, two famous leaders of peasant uprising in Chinese history including Huang Chao in the Tang Dynasty and Li Zicheng in the Ming Dynasty (1368AD-1644AD) both used to establish their capitals here for a short period. According to historical materials from the period between the Han and the Tang Dynasties, generally speaking, there were more than 88,000 permanent families living in the city of Chang‘an with a total population of over 240,000, making it one of the biggest and most prosperous cities in the world at that time.
What's more, during the process of excavation work on the site of Chang'an city in the Han Dynasty, relics of big wooden bridges were discovered, which were quite rarely seen in China. Nowadays all the Chinese people hope that the ancient relics of Chang'an city could be protected better. It is hoped to exist so long that all the human beings in the world would be able to learn as much as possible about the great ancient Chinese civilization.