Speaking of cold cases, many people have different views. There are countless difficult cases left over from thousands of years of historical development. There are many mysteries, such as the unknown disappearance or vague death of people, the disappearance and destruction of goods, the storage of treasures and so on. But when it comes to the biggest unsolved cases, I think it should be the sudden disappearance of Laozi, the founder of Taoism, the sudden death of Song Taizu Zhao Kuangyin and the mystery of the life and death of his emperor Zhu Yunwen.

First, the mystery of the disappearance of Laozi, the founder of Taoism, has never been solved. He founded Taoism and compiled the Tao Te Ching, and his contribution left a very valuable thing for future generations. Even Confucius of Confucianism worships him very much. But his sudden disappearance left a great mystery to people, and no one can confirm the whereabouts of Laozi until today. According to legend, he rode an ox through Hangu Pass and was never heard from again. Some people speculated that he was hiding in the mountains, and some people speculated that something had happened to him. Although there are all kinds of conjectures, no one has ever confirmed why Laozi disappeared.

Second, Zhao Kuangyin's sudden death is also puzzling. Speaking of Song Taizu and Zhao Kuangyin, everyone knows that with his efforts, he overthrew the tyranny and gave the boss a stable world. We have heard the story of him releasing soldiers with a glass of wine since childhood. His administration laid a certain foundation for the prosperity in the late Northern Song Dynasty. His death filled people with suspicion. It is said that Zhao Kuangyin died suddenly after his illness, but after his death, his younger brother stood in front of his bed with an axe. This makes many people wonder whether Zhao Kuangyin died of illness or was deliberately murdered by his younger brother, and the mystery of Zhao Kuangyin's death is not really recorded in the history books.

Third, the mystery left by Emperor Wen Jian to the world, no one knows whether he is dead or alive, because what disappeared. The emperors of the Ming dynasty were very powerful, and their way of governing the country was deeply rooted in the hearts of ordinary people. When Wen Jian was in power, he was threatened by other royal families, but the power of the vassal king was too great. Judy took the opportunity to usurp the throne and safeguarded the Ming Dynasty. However, his life and death has become a mystery in people's minds.

These three events are mysteries that people have not solved so far. Although there are many conjectures, few people can confirm them.