There are many legends and unsolved mysteries of civilization circulating on Earth.

For example, the Mayan civilization, such as the mystery of the pyramids in Egypt.

Such as prehistoric civilizations and so on.

Tang Mingyu, who studied archaeology, naturally knew all of this.

And the Phoenix civilization is the legend of the Tang Kingdom.

It is said that the ancient country of Phoenix thousands of years ago had a wisdom civilization that surpassed this era.

They introduced the melted water from the icebergs of the Northwest into the depths of the desert and established a nation in the depths of the desert.

And Fengcheng is the legendary city of Black Castle, which can resist the invasion of any foreign enemy.

At that time, the Great Han Kingdom wanted to take the Phoenix Ancient Kingdom, and sent hundreds of thousands of troops deep into the Phoenix Ancient Kingdom, but returned defeated.

It is rumored that Fengcheng was like a black fortress closed on all sides at that time, and the Han army had no place to attack, and the various weapons they used to attack the city were useless for the strong city walls of Fengcheng.

Hundreds of thousands of troops finally retreated, and only a few tens of thousands remained, and later the Great Han Kingdom no longer dared to invade the Phoenix Ancient Kingdom.

Tang Mingyu scoffed at these legends when she learned about them from the original host, and she didn't believe them at all, but now that she saw that the walls of the underground Phoenix City were such a solid alloy, she began to believe that this legend was true.

How can a city wall built of these alloys be able to penetrate with ordinary weapons, even with modern ordinary shells.

Knowing this, Tang Mingyu was extremely excited in her heart, if she could discover that the Phoenix Civilization really existed in this different time and space, it would definitely be a very meaningful thing for her.

Moreover, Tang Mingyu is also full of expectations for the metallurgical technology of the ancient country of Phoenix, which is definitely not inferior to modern metallurgical technology, and this black alloy is probably enough for the manufacture of aircraft carriers.

Tang Wuji was also shocked to see this black city wall so strong, with his imagination, he would never have imagined that there was such a strong city wall in the world.

"Father-in-law, let's go find the East Gate."

Although it was difficult to discern the direction in the underground dark river, Tang Mingyu was still able to distinguish between east, west, north and south according to the instructions of the mark, and she believed in the wisdom of the builder of the Phoenix Ancient Kingdom.

Following the marked route, Tang Mingyu and Tang Wuji, father and daughter, soon came to a place that clearly looked like the gate of the city.

Unfortunately, the city gate is locked, and the city wall is more than ten zhang high, and there is also a sloping cap on it, so that people can't climb into it at all.

Tang Mingyu saw this pattern of Fengcheng and thought that Fengcheng was called the Black Iron Castle, and she couldn't help but be amazed in her heart.

How do I get in?

Tang Mingyu began to carefully observe the city gate, and found that the city gate was carved with all kinds of lifelike phoenixes, she counted them carefully, exactly nine, which can be seen to represent the meaning of nine phoenixes.

Fengcheng is rumored to have been built by the Empress of the Nine Phoenixes, and now that Tang Mingyu sees the Nine Phoenixes at the door, it seems that he has also verified this.

Except for the carved phoenix, the gap between the gate and the door frame is very small, and it can be described as a perfect fit.

At this time, Tang Wuji put his hands against the door and tried to push hard.

Tang Wuji is now a peerless master, and a push at will is also a thousand powers.

Unfortunately, the gate remained untouched.

At this time, Tang Mingyu suddenly saw some red light appear on the nine phoenixes on the gate.

What does this sudden red light mean?

However, Tang Wuji reacted quickly, and his face changed and said, "Xiaoyu, there is a mechanism." ”

Sure enough, as Tang Wuji's words fell, some dark compartments suddenly opened next to the door, only to hear the sound of swishing, and a large number of black arrows shot towards the two of them indiscriminately.

Fortunately, both of them are top masters, even in the water, they are very flexible, either dodging or pushing away, so that these black arrows lose their due threat.

After a while, the arrows stopped shooting, and the secret grid was closed, and it was restored as before, and there was not a single gap in the black city wall, which made Tang Mingyu and Tang Wuji look at each other in shock.

This mechanism is really ingenious, if it were an ordinary martial artist, I am afraid that he would have died under hundreds of arrows.

Tang Mingyu found the scattered arrows from the water, checked the imprints on them, and found that the arrows all had the mark of the Phoenix Ancient Kingdom - Nine Phoenix.

And these nine phoenix marks, Tang Mingyu found through careful observation that they were not carved, but a very advanced printing technique.

You must know that although the Tang Kingdom now has printing technology, it is still relatively backward, and it can only be printed on paper and cloth, and printing on metal cannot be realized, let alone after thousands of years to be vivid.

And this kind of printing appeared in the ancient country of Phoenix thousands of years ago, which shows that the Phoenix civilization is real.

Discovering this, Tang Mingyu felt more and more expectations for the Phoenix Ancient Kingdom and the Phoenix Civilization in his heart.

Through these days of contact, Tang Wuji found that his righteous daughter knew much more about astronomy and geography than he did, in addition to admiring in his heart, he was completely centered on his daughter in this operation, which would also help but ask: "Xiaoyu, how do we get in next?" ”

Tang Mingyu pondered for a moment and said, "Father-in-law, don't worry, let Xiaoyu take a good look at it again." ”

Cautiously approaching the door again, Tang Mingyu once again carefully observed the city gate with a folding fan as high as more than ten zhang and a few zhang wide.

Before, Tang Mingyu's attention was all on the nine lifelike phoenix carvings, but now when the red light began to fade gradually, she suddenly found that there was a gap as thin as a cicada's wings about one meter and three meters away from the city gate.

Carefully approaching the gap to observe, Tang Mingyu found that the gap was very thin, about a dozen centimeters wide.

This width is larger than the width of the Nine Phoenix Jade Cards, so it can be seen that it cannot be opened with the Nine Phoenix Jade Cards.

Tang Mingyu recalled that the map drawn by the desert red cloud did not have instructions on how to enter the east gate, and according to that map, it should not be the east gate.

Is it to look for the entry location of the desert red cloud marker, or to continue looking for a way to open the east gate?

Tang Mingyu hesitated for a moment, then pointed to the gap and said, "Father-in-law, this gap may be the keyhole to open the door, but unfortunately we don't have the key, or let's go back first." ”

Tang Wuji nodded and said: "It's okay, this door weighs at least tens of thousands of catties, plus there is a machine inside, without the strength of the two of us, we may not be able to push it open, not to mention that there must be some unknown mechanism here, let's temporarily retreat it first, and then talk about it." ”

The two of them retreated helplessly, Tang Mingyu's eyes left from the gap, and when he turned around, his hand was on his waist, and a flash of inspiration flashed in his head, and he immediately thought of the Jiufeng Chaoyang Knife on his waist.

The widest part of the middle of the Nine Phoenix Chaoyang Knife seems to correspond to that gap, could it be the key to enter Fengcheng?

Tang Mingyu thought of this, and immediately said, "Father-in-law, wait, I really want to know how to open this door." ”