Video spoilers history, starting with the blitzkrieg on Poland

The video ends here, and comments start to fly out.

"During the Great Flood, it rained for millions of years."

《Where does rain come from? We now know that rain is the evaporation of water from the ground and then cooling, but what about the rain before that? 》

"It seems that the water on Earth came from Mars. After Mars lost its oxygen and hydrogen, most of it went to Earth."

"Mars was once a planet covered with oceans."

《Brought from the planet Nibiru.》

"Anyway, it's not something that comes from the Earth itself. Even if it rains for billions of years, the total amount of water won't increase. It still depends on comets hitting the Earth."

"Yes, many comets are just a mass of ice."

"The Earth was probably numbed by countless comets in ancient times."

"If you are indecisive, you will crash into the earth. The moon will crash into the earth, mass extinction will crash into the earth, and water will also crash into the earth."

And in the Tang Dynasty.

Li Bai saw that his initial guess was almost correct, and he couldn't help feeling happy.

"Haha, that's it."

"The water of the Yellow River comes from the sky!"

"The water of the Yellow River comes from the universe."

"According to Tianmu, the water in a living human body may also come from the universe."

"I never thought that we, ordinary people, could have a connection with things thousands of light years away in the deep space of the universe."

“The sky canopy is truly amazing!”

When his thoughts became exciting, Li Bai couldn't help but feel inspired to write poetry.

He took out a pen and recorded the brilliant ideas in his mind.

If nothing goes wrong, it is a classic ancient poem written by Li Bai about the wonderful relationship between the universe and the earth's water resources.

It is about to be born again.

And soon, a new sky appeared.

The sky curtain raised a question.

[Why did so few princes go out to lead troops to fight in ancient Chinese history? ]

[There were quite a few emperors who personally led the army to fight. ]

[But if you count carefully, there were so many dynasties in ancient my country, and there were very few princes who led troops to fight in wars. ]

[If the emperor did not lead the troops himself, he would often order his son to lead the troops.]

【But even the emperor's son led the army to war. 】

[Often, it is the sons of others other than the crown prince who lead the troops.]

[Giving military power to other sons also caused a lot of problems. ]

[These princes who led troops to fight and had their own armies and authority, after becoming familiar with the army and having military merits, their personal strengths skyrocketed. ]

[On the contrary, it may pose a threat to the crown prince or even the emperor himself. ]

[But even so, there are so many precedents. ]

[However, in history, it is still rare for a prince to personally lead an army to war. ]

【Do you know why? 】

Late Han Dynasty.

I just read Guan Yu in Zuo Zhuan a few days ago, stroked my beard, laughed and said:
"Your heir cannot lead a teacher."

"As the heir to the emperor, the crown prince, with his noble status, should be primarily responsible for managing and supervising the entire country, rather than personally leading troops out to fight."

"This truth is very obvious. Tianmu doesn't need to ask at all."

And in the Sui Dynasty.

When Yang Guang saw this question, he smiled slightly.

I couldn't help but think of what happened back then.

I also said silently in my heart:
"Thanks to this tradition, otherwise I might not be able to get the position."

The same gratitude also occurred in the Tang Dynasty. Li Shimin also said silently:
"Anyway, if it weren't for the tradition that the crown prince doesn't personally lead the troops into battle."

"I probably wouldn't have had as many opportunities to make military achievements as I did back then."

For this simple question,

Most of the ancient people were able to give some relevant reasons.

And the sky curtain also explained.

[First of all, on the surface, the crown prince is the next emperor and the executive vice emperor. ]

[Given his noble status, there is really no need for him to lead troops to fight.]

【Even if we win, there is nothing left to seal. 】

[But there is another reason, which is that after most dynasties appoint a crown prince, they will form a group around the crown prince. ]

[After all, the bureaucrats and nobles, big and small, not only had to flatter and curry favor with the old emperor, but also had to establish a good relationship with the prince in advance to maintain the power and wealth of the next generation.]

[Even many princes set up their own teams and had partial administrative and military power.]

【Many times, the interior of a dynasty. 】

[The crown prince himself is the person who poses the greatest threat to the imperial power.]

[In this case, if we still let the prince go out to lead the troops to fight, he can improve his reputation.]

[After several battles, the prince became an invincible god of war. ]

[He holds 10 elite soldiers in his hands. ]

[The generals who followed the prince to conquer the world are also eager for the prince to take the throne immediately. ]

[If there is such a prince in the capital, do you think the old emperor can still sleep well at night? ]

[You know, the scene of a loving father and a filial son in front of the imperial power is being played out over and over again! ]

【And we must know that the crown prince is not only another power center besides the emperor. 】

【He is also an important figure in maintaining national stability. 】

[How many heroes, invincible emperors, fell because of the issue of succession, leading to the death and destruction of their country? ]

【In the context of the ancient feudal imperial society. 】

[Having a stable and clear successor is sometimes more important than winning a battle.]

[Even if the emperor was wary of the prince and didn't give him any real power, he just kept him as a lucky charm. ]

[But as long as the position of crown prince exists, he can serve as a substitute for the emperor.]

[If anything happens to the emperor, the crown prince can take over the throne immediately and legitimately, without causing the country to fall into civil strife.]

[Countries that did not appoint a crown prince generally fell into internal strife after the emperor's death. ]

[The better ones were internal strife in the palace, but the worse ones were the direct destruction of the country. ]

【Just like the current Vice President of the United States. 】

[On some key occasions, when the president appears in public, the vice president generally does not appear.]

[This is to prevent the situation where the heads of state are all implicated.]

[If the president is assassinated, the vice president can immediately take over and maintain stability. ]

[This is true even in modern society, let alone in ancient times.]

[The emperor can lead the army in person and then die. ]

[The emperor can also die unexpectedly, but he can guarantee the safety of his successor and the crown prince. ]

[Such a country can often continue smoothly. ]

[And if the prince is allowed to go out to fight, what if he loses and dies? ]

[What if someone dies from acclimatization or exhaustion from traveling? ]

[Doesn't that mean there is no heir to the country? ]

[So if you really send the prince to fight, then you will have to find another prince of the prince.]

[In addition to the crown prince, create a backup crown prince. ]

[Is this okay?] (End of this chapter)