This is the Great Wall. It is an ancient defense project with the longest construction time and the largest amount of engineering in China and the world. Since the 7th and 8th centuries BC, the Great Wall has been built. The construction time has continued for more than 2,000 years, and the length is about 50,000 kilometers, which is a very vast project. When I was young, I always wanted to visit the Great Wall. Its historical features were too attractive to me. When I went to Beijing and finally boarded the Great Wall. At that moment, I felt that there was some kind of magical connection that connected me to ancient times. Let me know more about history.