This is called the most mysterious number, and it is the number seven in Arabic numerals. The number seven has a deep origin in China, so the number seven is also covered with a mysterious color, and it was also very yearning for the number seven in ancient times. For example, there are seven days in a week. Westerners believe that on the seventh day, God created human beings, so there are seven days in a week, which is one of the special meanings of seven. On the other hand, in ancient myths and legends, many people introduced the number seven. For example, it took Nu Wa seven days to create human beings. In the first six days, she created pigs, horses, cows, sheep, dogs and chickens, and on the seventh day, she created human beings. When ancient people created this myth and legend, why did they choose people who were created on the seventh day? So there is no reasonable statement so far. There is also a rumor about seven. We all know that Tanabata is on the seventh day of July. Tanabata is people's yearning for love. But what is puzzling is why it must be on July 7. According to myths and legends, the seventh day of July is the day when cowherd and weaver girl meet, which is decided by the heavenly queen. But why did you choose the seventh day of July? This has undoubtedly become one of China's unsolved mysteries. There are many rumors about the ancient number seven, and the most is the meaning of seven. Most people refer to seven lives, but why it is seven lives is an unsolved mystery. Moreover, when China created myths and legends in ancient times, many things could not be separated from them. For example, the Jade Emperor has seven daughters, but why only seven? Visible seven is a very mysterious number. There are many things related to seven. At 25 degrees Celsius, the PH value of acid-base neutralization is seven, so there are too many origins of seven in this world. Moreover, in ancient times, people had many definitions of seven, which reflected the special significance of seven.