The northern section is the Great Wall north of the Yellow River along the Wolf Mountain in the western section of the Yinshan Mountain, eastward to the northern foot of Daqing Mountain, and then eastward through present-day Inner Mongolia Jining, Xinghe to Shangyi, Hebei, and then northeast through present-day Zhangbei and Weichang, Hebei, and then eastward through Fushun and Benxi to the southeast, and the end point is in Suicheng County, Hanlelang County (now the place where the Qingchuan River enters the sea in North Korea).

Compared with the modern Ming Great Wall, the scale of the Qin Great Wall is far less. In Guyang County, Inner Mongolia Autonomous Region, which is now close to Jiuyuan, there are remnants of the Great Wall built by the Qin Dynasty.

However, many people in later generations questioned the significance of Qin Shi Huang's construction of the Great Wall, and Jia Junfang of the Western Han Dynasty commented on this as "raising troops to attack from afar, greedy for the outside and vain for the inside, and seeking to be widespread, without worrying about the harm." 」。

Not long after Meng Tian's death, the Xiongnu easily crossed the Great Wall of Qin, not only recovering the original lost territory, but also invading Yan County and Dai County. It can be seen that the role of the Great Wall itself in resisting the Xiongnu is not as great as imagined.

Beginning in 220 BC (the 27th year of Qin Shi Huang), Qin Shi Huang built a large number of roads with Xianyang as the center and extending in all directions, similar to a modern highway, connecting the old roads in the original six kingdoms and expanding them. Li Si was one of the ministers in charge of the construction of the road.

Originally, Chidao was a road dedicated to the Son of Heaven, and it was originally built only to facilitate the First Emperor's parade, and military use was just an incidental function.

According to the "Hanshu Jiashan Biography", Qin Chi Road is 50 steps wide (6.9 meters today), and a tree is carried at intervals of about three zhang (7 meters), which is used to calculate the mileage of the road.

On both sides of the road, poplars are planted according to local conditions. Willow, locust, elm and other trees. The roadbed of Chi Road is thickened and "turtle back" shaped, forming a gentle slope to facilitate drainage, and the famous Chi Road includes Shangjun Road, Linjin Road, Dongfang Road, Wuguan Road, Western Road, Qin Plank Road and Qin Straight Road.

Among the many galloping roads, the Qin Straight Road is the most famous. According to the "Historical Records", the main purpose of Qin Shi Huang's order to repair the Qin Straight Road was to travel the world, so in the 35th year of Qin Shi Huang (212 BC), Meng Tian was appointed to build the Ganquan Palace (located in Yunyang). Northwest of Chunhua County, Xianyang City, Shaanxi Province) straight to Jiuyuan County in the depths of the desert. Reaching 1,800 miles, the project is quite huge, which can be called a military highway more than 2,000 years ago, not only to flatten the mountains. It is also necessary to split the mountains and fill the valleys. And the terrain is treacherous, and people are rarely there. Even crossed the Meridian Ridge at an altitude of 1,800 meters without avoiding it, but this straight road was not completed, but in the mountains of today's northern Shaanxi Province. The remains of the straight are still visible.

According to research, Qin Zhidao is completely artificial, every six to seven centimeters as a unit, the loess is fixed and hard, and then a layer of loess of the same thickness is planted, and then it is hard, this construction method is called "plate construction method", the soil that has been hardened by the plate construction method will become very solid, and plants can not germinate and take root on this soil. Hardening the loess every 6 to 7 centimeters to make it a straight road of 1,800 miles can be imagined to be very staggering.

However, the roads of the Qin Dynasty were not as solid as the concrete roads of later generations, and when it rained, the roads became muddy, and the chariots would leave rut marks on the muddy ground, and the road surface would leave hard wheel grooves when the weather was clear. Chariots with different wheels (i.e., tracks) with different wheels could travel differently from the grooves left on the road, which was the background of Qin Shi Huang's implementation of "car on the same track" (unified vehicle distance).

In order to facilitate the transportation of troops and materials needed for the conquest of Lingnan, Qin Shi Huang ordered the opening of the Baiyue Canal in the south of the country. After on-site inspection, it was found that the distance between the Xiang River, which flows northeast into the Yangtze River system, and the Kaijiang River, which flows south from Guilin into the South China Sea, is very short, only about 40 kilometres in current units. If these two rivers are dug up, the Yangtze River system can be connected to the South China Sea.

However, the water level gap between the Xiangjiang River and the Qijiang River is very large, and the project failed one after another, until Qin Shi Huang ordered the eunuch "Lu" (Shi Lu in the history books) to dig the canal, and finally in 214 BC with 36 water gates, the project of connecting the Yangtze River water system and the Pearl River water system was completed, which was called the Qin Digging Canal, and later because the upper reaches of the Kaijiang River were zero water, so it was also called the Zero Canal and the Mio Canal. After the Tang Dynasty, Fang changed its name to Lingqu, commonly known as the Steep River.

Located in Xing'an County, Guilin City, Guangxi Province, the Ling Canal is 36.4 kilometers long and 10 meters wide, and is composed of sub-projects such as the Tsubizui, the Large and Small Balances, the Discharge Balance, the South Canal, the North Canal, the Qin Dike and the Steep Gate.

The mouth is the main water distribution facility of the Ling Canal, located in the Xiangjiang River, 2.5 kilometers southeast of Xing'an County. When it is built, it is built with feldspar stacked all around, and the middle is backfilled with sand and pebbles, which is about 6 meters high, 23 meters wide, and 90 meters long.

The mouth divides the water of the Xiangjiang River into two streams, of which seven points of water are blocked by the water divider, so it flows along the big balance and flows to the Xiangjiang River through the North Canal, and the three points of water flow into the Qijiang River through the small balance and the south canal, which is the so-called "Hunan Seven Cents Three". For more than 2,000 years, it has been a waterway transportation artery between Lingnan and the Central Plains, and this project was designated as one of the national key cultural relics protection units in 1988.

In modern times, with the opening of the Guangdong-Hanzhou Railway and the Hunan-Guizhou Railway, shipping in the Ling Canal has gradually stopped, but until now, the Ling Canal is still used by local residents for domestic water and irrigation purposes. On the other hand, the water level of the Xiang River is raised instead of a water gate but as a "weir" to solve the problem of the water level difference between the Kai River and the Xiang River.

As early as Qin Shi Huang unified the six kingdoms, he began to build a large number of buildings for his palace, every time he destroyed a prince, he was on the hillside north of Xianyang, imitating the palace of the vassal state, ranging from Yongmen to the east to the intersection of the two rivers of Ling and Wei, there are overpasses and circular corridors between the palaces and houses to connect with each other, and put the captured beauties and bell drum instruments in it.

According to the "Historical Records of Qin Shi Huang Benji", during the construction of Afang Palace, Qin Shi Huang had planned to build 300 palaces in Guanzhong and 400 palaces outside Guan.

On the other hand, historical records also record that in the 35th year of Qin Shi Huang (212 B.C.), there were already 270 palaces within a radius of 200 li from Xianyang City, which were connected to each other by overpasses and corridors, and placed tents, bells and drums and beauties in them.

Name of the palace - historical records - remarks:

Liangshan Palace's "Sanfu Huangtu" is located in Youfufeng Haoqi County (now Qianxian County, Xianyang City, Shaanxi Province)

Qutai Palace's "Hanshu Jia Zou Meilu Biography" Eastern Han Dynasty Ying Shao said: "The first emperor is also governed, if the Han family is not in the Yang Palace. 」

Changle Palace's "Water Jing Note Volume 19 Weishui" is located in the south of Weishui, and its north is Xianyang Palace, and the two palaces are connected by Wei Bridge.

Lanchi Palace's "Yuanhe County Atlas" is located in the Tang Dynasty Xianyang County 25 miles east, in 216 B.C., Qin Shi Huang and four warriors were near the Lanchi Palace, encountered a robber attack.

Yichun Palace's "Sanfu Huangtu" was originally one of the palaces of Qin Shi Huang, located in the southeast of Chang'an City, east of Du County, near Xiadu.

Wangyi Palace "Sanfu Huangtu" is located in the boundary of Zhuoyang County, north of Zhuanshui, looking north is the place of Yidi, so it is the name of the palace. Qin II Hu Hai was forced to commit suicide by Zhao Gaowei in Wangyi Palace.

The bell palace "Sanfu Huangtu" is located in the northeast of Ju County 25 miles, should be Qin Shi Huang after the world's soldiers for the bell for the bell, the place where the bell is parked.

Xianyang Palace, "Sanfu Huangtu", "Historical Records of Qin Shi Huang Benji", Xianyang Palace was originally the place where Qin Shi Huang summoned Jing Huang. Qin Shi Huang and his ministers set up wine in Xianyang Palace. Qin Shi Huang used Xianyang Palace as a place to conduct daily affairs and for his ministers to receive orders.

In the twenty-seventh year of Qin Shi Huang, Qin Shi Huang ordered the construction of the Xin Palace in the south of Weishui, and soon renamed the Xin Palace to the Pole Temple to symbolize the North Star at the pole of the sky. From the pole temple opened the road to the mountain, and built the front hall of Ganquan, and built the road on both sides of the wall, from Xianyang to the mountain.

Xingle Palace "Sanfu Huangtu" was built during the Qin Shi Huang period, and was repaired many times in the Western Han Dynasty, with a circumference of more than 20 miles.

Afang Palace, also known as Acheng, is located on the south bank of Weishui, 14 miles northwest of Chang'an County (now Xi'an City) in Yongzhou, and was originally built during the reign of King Huiwen of Qin, but the death of King Huiwen put the construction of the palace on hold. (To be continued......)