The four dragon cities are located on the border of the Dragon Kingdom, guarding the four directions, which generally ensures that the current territory of the Dragon Kingdom is not broken.

It's a real border city!

There are also two dragon cities, one for military and one for research.

It is said to be military and research.

But whether it is or not, Su Bai doesn't know very well, it's just hearsay.

The Seven Dragon Cities, in fact, strictly speaking, they are not planned according to the aura of heaven and earth, except for the Dragon Capital.

But there is no doubt that these seven dragon cities all have very powerful military forces, which can be described as impregnable, and it is precisely because of this that today's dragon kingdom survives and continues to develop.

Especially the four dragon cities in the border land, they are like immortal gods, constantly attracting countless demonic beasts and monsters to compete with them!

It is also because of this that the thirty-six heavenly cities and seventy-two underground cities can develop steadily.

The Thirty-six Heavenly Cities and the Seventy-two Underground Cities are divided according to the aura and development level of heaven and earth.

As for why it is divided in this way, in fact, it is mainly a matter of resources.

After all, all cultivation resources need to be snatched in dangerous places, and it can be said that they are nine deaths, so how to get more cultivation resources and allocate more cultivation resources must rely on personal ability.

Cities that can cultivate more martial arts geniuses and make more contributions will naturally have more resources to be allocated.

But if you can't cultivate a lot of martial arts geniuses and make a lot of contributions, then I'm really sorry, resources will definitely not be able to give you, otherwise, others will have opinions.

It is also because of this gap that in addition to the Seven Great Dragon Cities, the remaining one hundred and eight cities will have fierce struggles.

However, the Thirty-six Heavenly Cities are relatively stable, and only the fluctuations of the Heavenly Cities with the number of rankings will be relatively large, and the rankings will be changed from time to time.

As for the seventy-two dungeons, the competition is fierce, so the ranking of the cities on the list of Disha Cities will change dramatically every time.

It is also because of this appearance that one hundred and eight cities are called thirty-six Tiangang Cities, and seventy-two Earth Evil Cities.

Qingyang City is ranked 70th among the seventy-two Earth Demon Cities.

As for such a ranking, in addition to cultivation resources and city contributions, the aura of heaven and earth also occupies a large factor.

As mentioned earlier, the concentration of heaven and earth aura in some places is very strong and the quality is very high, and the concentration of heaven and earth aura in some places is scarce and of low quality, and the same is true for the thirty-six Tiangang City and the seventy-two Earth Demon Cities.

For example, the reason why Qingyang City ranked seventy among the seventy-two Earth Demon Cities, in addition to its small contribution, was mainly because of the thinness of the aura of heaven and earth.

According to the explanation of the Dragon Kingdom Atrium Research Institute, the aura of heaven and earth between heaven and earth can be divided into three, six, nine and so on.

And the heaven and earth aura of Qingyang City is at most the lower third rank.

It means that the heaven and earth aura of Qingyang City can only support human beings to cultivate to the third rank of martial artists.

In fact, a long time ago, the heaven and earth aura of Qingyang City was not only the lower third rank, but even the middle fifth grade.

However, in the early days, the walls of Qingyang City had not been completely repaired, and it encountered a crisis, so the Federation warriors resisted desperately, and finally a martial artist broke through the bottleneck, from the fourth-grade peak martial artist to the fifth-grade martial artist, and in one fell swoop, all the cave demonic beasts that were committed were destroyed, and Qingyang City was saved.

It's just that although Qingyang City was saved, that martial artist broke through from the peak of the fourth rank to the first level of the fifth grade, but he absorbed a large amount of heaven and earth aura in Qingyang City, and it was also because of that appearance that the overall quality of the heaven and earth aura in Qingyang City fell from the middle fifth grade to the middle fourth grade.

And because of the development over the years, the heaven and earth aura of Qingyang City has declined again, and it has become a lower third-class.

However, just now, when Su Bai was running the basic exercises to absorb the aura of heaven and earth, he found that the aura of heaven and earth was not the same as what he had been exposed to before, and its quality and strength were higher, and it had already surpassed the lower third level and reached the level of the middle fourth rank.

This shocked Su Bai, and he couldn't help but open his eyes, looked at Chen Mu, and opened his mouth to ask, "The heaven and earth aura of the middle fourth rank?" ”

Seeing that Su Bai sensed it, Chen Mu smiled slightly, nodded lightly, and said loudly: "Not bad!" ”

"But...... How could this be?! ”

Su Bai didn't understand it very much.

The quality of the heaven and earth aura in each city is detected and sensed by a high-grade martial artist, and then the overall evaluation is carried out.

Because after these years of development, the atrium of the Dragon Kingdom has been researched to absorb a large amount of heaven and earth aura, which can be said to be the formation mentioned in the ancient books, the spirit gathering formation, which can absorb and gather the aura of heaven and earth together.

But because of the special material, there are not many such devices.

In an effort to maintain balance, there are some cities where Gathering Devices are placed.

However, Qingyang City has always been a third-class heaven and earth aura, and even if a middle and fourth-class heaven and earth aura really appears, it will inevitably be detected.

The question is, why is it not detected?

"Is it because of the Meditation Lake?"

Su Bai's eyes rolled slightly, his gaze fell on Chen Mu's body, and he asked softly.

"I think it should be, but it's only been two months since the last Heaven and Earth Spiritual Qi quality assessment, but here can overflow the middle and fourth-grade Heaven and Earth Aura...... I think it came after the assessment, plus the Lake of Meditation...... As we all know, this is a dating mecca, and it is only natural that few people will go deep into the depths of the Meditation Lake, so it is only natural that they will not be discovered. ”

"I see!"

When Su Bai heard this, he suddenly nodded in realization: "So, you have been cultivating here for the past few months?" ”

"Well, as long as there are no accidents, I will come here to cultivate, which is why my realm will be raised so quickly."

Chen Mu nodded lightly at Su Bai, opened his mouth and said: "However, although there will be a fourth-class heaven and earth aura, it only lasts for a period of time, I have studied a law in the past few months, almost until four o'clock in the afternoon, the middle fourth-class heaven and earth aura will continue to spray thin, and sometimes it will even reach the middle fifth level, but because it was too late, I didn't stay here longer, I doubt that the reason why such a level of heaven and earth aura is spewed back is that it is very likely that there is a treasure in the meditation lake!" ”

"In the Lake of Meditation? Got a treasure? ”

Hearing Chen Mu's guess, Su Bai was directly stunned.

He didn't expect Chen Mu to be able to guess such a reason.

"Yes, if you can go to the Lake of Meditation and get that treasure...... Do you think this will greatly enhance our strength? Chen Mu nodded lightly, his eyes fell on Su Bai's ordinary face, and he said softly.