On November 14, 1716, Leibniz, the father of calculus, famous scientist, writer, and even social activist, walked the streets of this ancient city for the last time. He should be the person who yearned for Chinese culture the most in modern European history. He specifically went to the French Jesuit Church to learn about Chinese culture. He was very interested in the Yin-Yang and Eight Diagrams. By the way, there is also a library built by him here. It can be regarded as the origin of modern libraries.