What is the most outstanding contribution of Qin Huang and Ying Zheng?

Unifying the six countries and building the Great Wall was the first emperor in China to complete reunification. He used the title of emperor for the first time and established the first unified centralized and autocratic country in China history-Qin Dynasty. Qin Shihuang's order to unify and simplify Chinese characters is a summary of the development and evolution of ancient Chinese characters and a great reform of Chinese characters, which has played an important role in the development of China culture. 1. unify the written language and make it the foundation of a nation, and continue to this day; 4. Abandoning the enfeoffment system and establishing counties and counties became the standard mode of management after the reunification of China, which lasted for thousands of years; 13. unifying currency and weights and measures will greatly promote domestic business exchanges. 4. The cars are on the same track and the roads are at the same distance. The construction of Qin Zhi Road greatly facilitates domestic traffic; 5. Burn the history books of the six countries, unify thoughts objectively, and avoid splitting the country due to historical problems; However, the destruction of ancient books in various countries has made a considerable number of ancient cultural faults and ancient history in China dating, which is really regrettable; 6. The construction of Lingqu strengthens the control over the Pearl River Basin, making this area the territory of China forever; 7. Build the Great Wall to make it a natural dividing line between agricultural and nomadic peoples, and the Great Wall will become a national border for a long time; 8. Expedite to South Vietnam and bring Fujian, Zhejiang and Guangdong into Chinese territory. 9. Attack the Huns in the north and recapture the Hetao area, making this area the territory of China forever. So far, the basic pattern of China's unified multi-ethnic centralized state has been established.