What ancient wisdom shocked modern people?

Although this earth-shaking change has taken place in the development of idle social science and technology, this kind of thing has only happened in fairy tales before, and now it has become commonplace. However, in an era of backward technology in ancient times, there are many things that modern technology can't accomplish. This is the technology and wisdom of the ancients. Although not as magical as modern technology, the wisdom of Gure is amazing.

When we talk about China, we think of the Great Wall in China. The Great Wall of China is famous all over the world. It is also called eight wonders of the world. The construction of the Great Wall is full of the wisdom of ancient craftsmen in China. At that time, it was the Qin Dynasty, and there were no building tools, modern cranes, excavators and bulldozers. The Great Wall was completely completed by this kind of manpower. How to complete such an arduous project by manpower is unimaginable to modern people.

Every stone used to build the Great Wall weighs several tons. I wonder how the ancients thought of cutting and transporting it. The most amazing thing is that the Great Wall has stood on the land of China for thousands of years, experienced numerous wind and sun, and even experienced many wars. But it still stands on the land of China, and it hasn't collapsed for such a long time that we modern people can't imagine how craftsmen at that time designed and built the Great Wall.

In our modern times, there is this kind of memory metal, which is the most advanced product of our science and technology, but this kind of memory metal existed in ancient China. There is a sword in the tomb of Gou Jian, King of Yue, which has been bent by heavy objects for thousands of years. After modern archaeologists found it, they took out the heavy objects again, and the sword miraculously recovered its original state, and it was stainless for thousands of years. This craft far exceeded the craft at that time, and I have to admire the magic of the craftsman's wisdom at that time.