There have been human beings in the Chang'an area for a long time, as early as 1 million years ago, the Lantian people built shacks here; 7,000 years ago in the Yangshao culture period, there was already a rudimentary form of the city wall here, and the Banpo site is the representative of Yangshao culture. In 2008, the discovery of the Yangguanzhai site in Gaoling, the first of China's top ten archaeological discoveries, advanced the history of East Asian cities to the late Neolithic period, 6,000 years ago, in a settlement the size of 40 standard football fields, perhaps the earliest city in East Asia, with a 1,945-meter-long ring moat on the edge of the city. At that time, there was already a simple division of labor in society, some ancients made pottery for a living, some cultivated the land, and some hunted. In addition to blood relationship, there is also some kind of system that maintains interpersonal relationships.

"Nine days to open the palace, all countries to worship the crown", Chang'an in its heyday of development has always served as the center of the Oriental world, attracting a large number of foreign envoys and worshippers.

Chang'an has shown the national spirit of self-confidence, openness, atmosphere, tolerance and devotion to civilized China to the world, and has created a cultural highland that the descendants of Yan and Huang will always be proud of.

"The history of a city is the history of a nation", Chang'an, the capital of Chinese history and culture, has become a negative piece of Chinese history, a business card of Chinese culture and a chip of Chinese spirit with its graceful elegance, full of economy, erudition and wisdom, and magnificence inherited from generation to generation.

The famous Silk Road started from Chang'an. Chang'an is the first of the four ancient capitals of China, and it is also one of the four ancient capitals of the world, along with Athens, Rome and Cairo.

"Chang'an City" was called "Feng Ho" in the Western Zhou Dynasty. "Feng Ho" is the joint name of Feng Jing and Hao Jing, which were built by King Wen of Zhou and King Wu of Zhou respectively. The area where "Feng Ho" is located is called "Zongzhou". In the Qin period, it was called "internal history". In the early years of the Western Han Dynasty, Liu Bangding was in Guanzhong. In the 5th year of Gaozu of the Western Han Dynasty (202 years ago), Chang'an County was placed. A new city was built in the territory of Chang'an County, named "Chang'an City", which means "long-term peace and stability", and the area where Chang'an City is located was changed to "Jingzhao", which means "the land of Gyeonggi".

Since the opening of the Silk Road, "Chang'an" has become the center of oriental civilization. "Xi'an City": Fengjing (Zhou) - Haojing (Zhou) - Xianyang (Qin) - Chang'an (Han) - Chang'an (Xin) - Chang'an (Northern and Southern Dynasties) - Daxing (Sui) - Chang'an (Tang) - Chang'an (Later Liang) - Chang'an (Later Tang) - Chang'an (Song) - Chang'an (Yuan) - Chang'an (Ming) - Chang'an (Qing) - Xijing (Republic of China) - Xi'an (People's Republic of China)

The Chang'an region has long been the capital of the Zhou Dynasty in China, and the earliest record is that the Western Zhou Dynasty capitals were Xujing and Haojing (1111-770 BC).

Hokyo is also known as the Ho Ho, and Ho and Ho were originally two large-scale cities built along the Ho River. The west of Fengshui is called Yujing, and the east of Fengshui is called Haojing. The history is known as "the two capitals of the pickaxe", which were built by King Wen of Zhou and King Wu of Zhou respectively. However, it is customary to think of these two cities as one, as each has a different role. In the late Western Zhou Dynasty, Yujing assumed more of a religious role in sacrifice, while Hojing existed as an administrative center.

The Qin Dynasty built the capital of Xianyang, and the geographical location of Xianyang in ancient times was on both sides of the Wei River, covering part of today's Xi'an and Xianyang.

At the end of the Qin Dynasty and the beginning of the Han Dynasty, Chang'an was a township in Xianyang, the capital of Qin, and was the fief of Chang'anjun, the brother of Qin Shi Huang. Therefore, it is called "Chang'an". At the beginning of the Han Dynasty, Gaozu Liu Bang issued an edict, and Xiangguo Xiao He presided over the construction of the capital Chang'an, which opened the grand foundation of the Han Empire.

In 202 BC, Liu Bang defeated Xiang Yu. Han Gaozu originally wanted to build the capital Luoyang, but later Lou Jing suggested that the capital be Guanzhong, but most of the ministers came from the east. They all objected, thinking that Luoyang was better. So Liu Bang consulted Zhang Liang. Zhang Liang said: "Although the Eastern Zhou Dynasty, where Luoyang built its capital, was better than the Qin and Jin dynasties, the city was only a few hundred miles. The fields are too thin and flat on all sides, making them vulnerable to attack. On the other hand, there are thousands of miles of fertile fields in Hangu Pass and Longshu in the pass, there are rich Bashu in the south, and there is the convenience of Hu people's animal husbandry in the north, which can be defended on three sides, and contain the princes to the east. It is the so-called golden city of thousands of miles, the country of abundance. Lou Jing was right. So Liu Bang decided to set the capital of Chang'an, and worshiped Lou Jing as Langzhong, and gave Liu the surname.

In the fifth year of Emperor Gao of the Han Dynasty (202 BC), Chang'an County was placed, and in the seventh year of Emperor Gao, the capital was set here. Liu Bang began to rebuild the palace on the south bank of the Wei River, the north side of Afang Palace, and the Qin Xingle Palace, and named it Changle Palace. In the seventh year of Gaozu (200 years ago), Weiyang Palace was built, and in the same year, the capital was moved here from Liyang City, and it was named Chang'an City because it was located in Chang'an Township. Emperor Hui of the Han Dynasty built the city wall from the first year (194 BC) to the fifth year (190 BC). Emperor Wu of the Han Dynasty set up Jing Zhaoyin to govern Chang'an, carried out a large-scale expansion of Chang'an City, built the North Palace, Gui Palace and Mingguang Palace, and expanded the Shanglin Garden in the west of the city, excavated the Kunming Pond, and built the Zhang Palace.

In the more than 200-year history of the Western Han Dynasty, Chang'an has always been the political, economic and cultural center of the country. Since Emperor Wu sent Zhang Qian to the Western Regions to open a trade route, Chang'an City has become a bridge connecting Europe and Asia and the starting point of the "Silk Road", and it has prospered for a while. In its heyday, such as the second year of the first year of Emperor Ping of the Han Dynasty (2 years), there were 88,000 households and 246,000 people in the city, making it the first city in Chinese history with a large scale and many residents. At the end of the Western Han Dynasty, during the reign of Wang Mang, Chang'an City was destroyed in the war. To the Eastern Han Dynasty Guangwu Emperor Liu Xiuding capital Luoyang, Chang'an changed to Xijing. At the end of the Han Dynasty, Emperor Xian of the Han Dynasty moved the capital back to Chang'an. During the Han Dynasty, Chang'an has always existed as the capital.

Located in the northwest suburbs of present-day Xi'an, the city of Chang'an covers an area of about 36 square kilometers, about four times the size of Rome at the same time. Chang'an City has 12 gates and 8 main streets, with the longest street being 5,500 meters long. The palaces, noble residences, government offices, and temples in the city occupy about two-thirds of the city's area. The palaces are concentrated in the central and southern parts of the city, including Changle Palace, Weiyang Palace, Gui Palace, North Palace and Mingguang Palace. Among them, Weiyang Palace is the place where many emperors lived and dealt with government affairs starting from Emperor Hui of the Han Dynasty, and is one of the most famous palaces in Chinese history. The residential areas are located in the northern part of the city and are divided into 160 "Luli". The market is in the northwest corner of the city and is called the "Nine Cities of Chang'an". In the west of the city, there is a large area of Shanglin Garden, and there are mainly Kunming Pond, Jianzhang Palace and so on in the garden. In the south of the city, there is a group of ceremonial buildings built during the Wang Mang period. The Chang'an City of the Han Dynasty changed the pattern of large and small cities in the Warring States Period, and concentrated the residential areas, industrial and commercial areas and palace areas in one city, and the capital cities of later generations followed this system.

The ruins of the city wall of Chang'an City in the Han Dynasty are basically intact, and the rammed earth is clearly layered and unusually strong. According to the measurement, the circumference of the city is 25.7 kilometers, nearly 63 li in the Han Dynasty, with a total area of about 36 square kilometers, the east wall is 6 kilometers long, the south wall is 7.6 kilometers long, the west wall is 4.9 kilometers long, and the north wall is 7.2 kilometers long. In terms of today's place name, the northwest corner of the city is in Liucun Fort, the northeast corner is in Sanguanmiao, the southwest corner is in Yanque Gate, and the southeast corner is in Gelaomen, and the scope is extremely clear. The shape of the city is irregular squares, with palace districts to the south and residents, crafts and market districts to the north. In the city, the acacia and elm are shady, the pines and cypresses are luxuriant, the scenery is lush, and it is very spectacular.

The irregularity of the city wall of Chang'an in the Han Dynasty is completely affected by the Wei River, the Wei River, the terrain and the location of Weiyang and Changle Palaces, and it is not intended to build the city into the shape of the "Big Dipper" and "South Dipper". The north wall has 6 twists and turns, which are completely consistent with the direction of the Wei River. The west wall has 1 twist and turn, which is restricted by the Weihe River and Weiyang Palace, and the south wall is a right-angled twist and turn, in addition to being affected by the position of the two palaces, it is mainly to encircle the high ground into the city. The shape of Chang'an City in the Han Dynasty is completely restricted by geographical conditions, and adapting measures to local conditions is the basic principle of building Chang'an City in the Han Dynasty.

There are three gates on each side of the city wall of Chang'an City, and there are twelve gates in the capital. And the Xuanping Gate of the east wall (the first gate of the east out of the north, also known as the East Capital Gate), the Bacheng Gate (the first gate of the east out of the south, also known as the green gate), the Xi'an Gate of the south wall (the first gate of the south out of the south, also known as the flat gate) and the straight city gate of the west wall (the second gate of the west out of the south, also known as the Longlou Gate), have been excavated, and it has been confirmed that each gate has three doorways, each of which is 8 meters wide. The streets leading from the gates to the city are made up of three parallel streets. The width of the street is generally about 45 meters, with the middle one about 20 meters wide and each side about 12 meters wide, with two parallel drainage ditches as the dividing line. In fact, there are only eight streets like this, all of which run north-south and east-west, and are very straight, which is obviously closely related to the flat terrain. Because the Bacheng Gate, the Covering Gate, the Xi'an Gate, and the Zhangcheng Gate were too close to the court, the streets leading to the city were not included in the number of streets. The middle avenue, which is about 20 meters wide, is called "Imperial Road" or "Chido", and it was reserved for the emperor, and even the crown prince did not dare to cross it. When Emperor Cheng of the Han Dynasty was the crown prince, Emperor Yuan had been urgently summoned into the palace, Emperor Cheng who lived in Guigong (north of Weiyang Palace), after going out of the Longlou Gate, because he did not dare to cross the "Chi Road", he went west to the Zhicheng Gate, only to cross the "Chi Road", and "also entered the room door" into the Weiyang Palace. This proves that the management of the "Chi Road" in the Western Han Dynasty is very strict, and even the crown prince does not dare to do the "Chi Road". These criss-crossed streets form many "T-junctions" and "crossroads". The longest is Anmen Avenue (5.5 km) and Xuanpingmen Avenue (3.8 km). The shortest is 850 meters from Los Angeles Gate Street. The rest of the streets are mostly about 3 kilometers long. In addition to the men, these streets are Zhangtai Street, Zhangtai Street, Zhichengmen Street, Qingmingmen Street, Xiangmuro Street, and Hengmen Street. Due to the crisscrossing of various streets, the whole city is divided into areas of different sizes, which is called Luli in the general history books. (To be continued......)