(1) Papermaking: In the first year of Yuan Xing in the Eastern Han Dynasty (A.D. 105), Cai Lun made plant fiber paper suitable for writing with bark, broken fishing nets, rags and hemp heads as raw materials, and improved the papermaking technology, making the paper a widely used writing material. Known as Cai Hou paper. "

(2) Compass: a simple tool for determining the direction. Originally known as Sina. The main component is a magnetic needle (commonly known as a magnet) that can rotate freely on the shaft. The magnetic needle can be kept in the tangential direction of magnetic meridian under the action of geomagnetic field. The north pole of the magnetic needle points to the geographical south pole, which can be used to identify the direction. Commonly used in navigation, geodesy, tourism and military.

(3) Gunpowder: made of a mixture of saltpeter, sulfur and charcoal. At that time, people used these three things as medicine to treat diseases, so they were named gunpowder, which means medicine on fire.

(4) Movable type printing: woodblock printing, which began in the Sui Dynasty, was developed and perfected by Bi Sheng, Song Renzong, resulting in movable type printing, which was spread to Europe by Mongols, so Bi Sheng was later called the ancestor of printing.

2. Terracotta Warriors and Horses of Qin Shihuang

Terracotta Warriors and Horses of Qin Shihuang are a category of ancient tomb sculptures. In ancient times, human sacrifice was practiced, and slaves were accessories of slave owners before their death. After death, slaves should be buried with slave owners, which is a kind of sacrifice. Terracotta warriors and horses were made into sacrifices in the shape of troops (chariots, horses and soldiers)

3. Forbidden City

The Forbidden City is located in the center of Beijing, formerly known as the Forbidden City. It is the imperial palace of Ming and Qing dynasties, an unparalleled masterpiece of ancient architecture, and the largest and most complete ancient wooden structure complex in the world.

4. Dunhuang murals

Dunhuang is a county-level city under the jurisdiction of Jiuquan City, Gansu Province, state-list famous historical and culture cities. Dunhuang, located on the Silk Road, the main road leading to the western regions, Central Asia and Europe in ancient China, once had prosperous commercial activities. It is famous for Dunhuang Grottoes and Dunhuang frescoes, and is the location of the world heritage Mogao Grottoes and Yumenguan and Yangguan on the border of the Great Wall in Han Dynasty.

5. Dujiangyan Water Conservancy Project

In 256 BC, during the Warring States Period, the Dujiangyan water conservancy project led by Li Bing, the prefect of Shu County of Qin State, was located on the Minjiang River on the west side of Dujiangyan City in the west of Chengdu Plain, Sichuan Province, 56 kilometers away from Chengdu. Large-scale water conservancy projects are still irrigating farmland, which is a great water conservancy project that benefits the people. It is characterized by long time and no dam to divert water, and it is the originator of world water conservancy culture. This project is mainly composed of Yuzui diversion dike, Sha Fei weir spillway, Baokou intake, Baizhang dike, herringbone dike and other ancillary works. Scientifically solved the problems of automatic diversion (fishmouth diversion dike divides water into four or six parts), automatic sediment discharge (fishmouth diversion dike divides sand into two or eight parts) and control of incoming water (Baokou and Sha Fei weir), thus eliminating floods.