Ji Tianci didn't know how long he had been sinking in this bottomless tunnel, but what made him feel interesting was that sticking to the inner wall of this tunnel was like a slide.

The "slide" twists and turns, shining with light, as if you are in a crystal cave.

Gradually, Ji Tianci saw a trace of red light appear in the tunnel under his feet. The red light grew brighter and brighter, and at last, when I saw the exit, there was like a burning flame.

"Chirp~~~"

Ji Tianci slid out of the hole, and a fiery red world appeared in front of him, and he could see the margin.

Heaven and earth are within reach, and the ground is black and red under your feet, perhaps the color of the land is black, and it is the bonfires burning everywhere that make this place fiery red and translucent.

Falling down the "slide" will lead you to a huge lake, and at this time, the transcendents are smoothly guiding the mortals to the surface.

In the distance, heaven and earth are connected, and countless red stone pillars grow on the gray-black earth, these stone pillars seem to be naturally formed, each of which is like a pillar, connecting the "heaven" here.

Some of them grow straight, while others tilt in different directions. The thick one can be one kilometer in diameter, and the thin one is like a skyscraper.

These stone pillars of different shapes are interspersed with a large number of houses, and their architectural styles are even more diverse, ranging from Chinese courtyards to European castles, pavilions and central gardens. Ji Tianci guessed that these architectural structures should have been stolen from the outside world by Hao Miao.

The city is divided into several areas by a turquoise river, which also serves as the city's main transportation artery, and many small boats are moored along the river, presumably for the mortals who come here.

People often ask, "How high is the sky?" No one can give an accurate answer, because "day" is only a vague concept.

But the "day" here can be measured accurately. Its highest point is only 512 meters above the ground. The whole space here is like a 512-meter-high earthen box on the boundary of a large city.

Ji Tianci thought that the "sky" here was also composed of rock and soil, but he didn't want the sky here to be red and blue. Like a huge blue mirror, reflecting the fiery red light of the ground.

The top of the city is covered with a layer of pale blue ice crystals, which are like a canopy of heaven. But at first glance, it is not a natural formation, but more like a huge project of aquarium manufacturing.

Ji Tianci didn't understand what this canopy was for, but in terms of visual effects, it reflected the scene below, which would make people feel that the space here was much more spacious.

Created by heaven, this place is prosperous and magnificent at a glance, like an underground city in the science fiction world.

The whole city is not smaller than Wuyang City, and if high-rise buildings are built, it is estimated that it can accommodate tens of millions of people.

However, the city may have had its population relocated before the vastness. Ji Tianci didn't see the aborigines, there were only more than 100,000 "outsiders" here, and it was more than enough to live in.

Everyone is busy, busy moving into their new accommodation. Cities have long been planned, and people from all over the world know where to live based on their architectural styles.

In the space at a height of 500 meters, transcendents are flying around, making this place look so lively.

Everything here seems to outsiders to be so new, flowers and trees seem to grow in greenhouses, they stand there quietly, only the air currents caused by the extraordinary whistling can make them shake their bodies.

Ji Tianci and Yuwen Zhi fell beside Hao Miao. The eyes of the two were still looking around, and Ji Tianci's eyes were incredible.

"Well, I'm good here! I've renamed this city 'Refugee City.'" Hao Miao said proudly.

Ji Tianci was speechless, "Can't you choose a nice name?"

"Refugee city is more appropriate!"

Ji Tianci ignored him anymore, and after taking a deep breath, his face suddenly became surprised again, "I just found out that there is oxygen here?"

Hao Miao rolled her eyes, "Isn't this nonsense, without oxygen, how can mortals live." ”

"But where does this oxygen come from? I feel like the oxygen level here is higher than the outside world. ”

Ji Tianci's questioning eyes looked at Hao Miao a little embarrassed, in fact, Hao Miao couldn't explain where the oxygen here came from. He had found countless enclosed spaces in the earth's mantle, most of which were devoid of oxygen, and only these 134 could be inhabited by mortals.

At this time, Hao Miao coughed, and in order to hide his embarrassment, he said: "You can ask Yuwen Kehuang this question, he is a prophet, he knows everything." ”

Yu Wenzhi smiled indifferently and explained seriously: "We are now located between the 'upper mantle' and the 'lower mantle', where the geological structure is rich in magnetite and hematite, these two minerals will release a large amount of oxygen-rich fluids when they decompose, and these fluids form a liquid oxygen layer in the earth's interior, which contains eight to ten times more oxygen than the earth's atmosphere.

In addition to oxygen, the Earth's mantle also stores a large amount of water, about three times the volume of the world's oceans. I speculate that in the early days, there were no oceans on the surface of the earth. It is the huge amount of oxygen in the mantle that causes chemical changes in the Earth's interior, causing water stored in the mantle to gush out of the surface, thus forming the ocean.

In fact, the water in the mantle is all freshwater. The pristine seawater was not originally full of salt, and it was originally freshwater, just like the water of the rivers.

However, the earth's water is constantly circulating, and every year a large amount of water evaporates from the surface of the ocean, and some of this water is transported to the land through atmospheric movements, and then forms precipitation and falls to the ground.

Rainwater washes away the soil, destroys rocks, and carries dissolved materials from the land, mostly salts, into the rivers, which return to the sea. As a result, about 3 billion tonnes of salt are brought into the ocean every year, and the ocean becomes a shelter for all dissolved salts.

During the evaporation of seawater, the salts of the income cannot be lifted with the water vapor and have to remain in the ocean. Over and over again, the salts in the ocean accumulate and the sea becomes saltier and thinner.

Most of the entrances to the mantle that Shui Zhenghao found were in the ocean, also because these entrances were formed when water from the mantle erupted from the surface in the earliest periods.

The liquid oxygen and mineral layers around us act like an incubator to isolate the temperature of the Earth's core, keeping the temperature here at around 16 degrees Celsius. Therefore, we don't feel any discomfort standing here, except that there is no sunlight, and the other conditions are even more comfortable than the outside world. ”

After Yuwen finished speaking, Hao Miao nodded again and again, "Yes, yes, yes, that's it." ”

Ji Tianci looked up again, pointed to the "canopy" and asked, "You made this?"

"Yes!" Hao Miao replied loudly this time.

"What is this for? Make the city brighter?"

"It's not...... Some stones sometimes fall from it, which is a great threat to mortals, and this is to protect the city. ”

"I see...... You don't have an electrical system here?" Ji Tianci asked again.

"What kind of electricity do you want...... Ignition lighting is sufficient. ”

"Transportation depends on rowing?"

"There are rickshaws too, but the ground is uneven, so it's better to walk......"

"Social networks are all about shouting?"

"We also have extraordinary postmen...... Cross-city letters can be delivered in a day. Between the people of the same city, they directly rowed to meet and communicate. ”

"You're really backward here! Why don't you bring in the phone from the outside world?"

"There's no signal here......"

“……”

Ji Tianci and Hao Miao chatted while walking. Hao Miao's mood at this time was like an outsider entering his "boudoir", which made him feel embarrassed.

Yu Wenzhi also sighed at this time, "It is precisely because of the backwardness here and the fact that the common people do not understand the outside world, so everyone is very satisfied with the current life." Some eat and some wear, and good health is the greatest happiness. ”

Hao Miao also nodded, "Yes, most of my people here have never left the city they live in their lives. The highest ideal of the transcendents is only to be a city lord. ”

Ji Tianci was a little puzzled again, "Why has your Star Floating Island developed so slowly for thousands of years? It stands to reason that there should also be some special inventions and creations in your civilization." ”

Hao Miao didn't know how to answer.

Yu Wenzhi said: "Because they lack struggle. During the three thousand years from the Zhou Dynasty to the Qing Dynasty, Jiuyou's development was also very slow. But in the past 100 years, Jiuyou has been experiencing invasion wars, people have a strong sense of crisis, and everyone has been working hard to strengthen their homeland, even if there is no war, there has always been an imaginary enemy in people's hearts. The same is true of all powerful countries, and it is the enemy in the hearts of the people that promotes the development of the entire scientific and technological civilization. ”

At this time, Yu Wenzhi raised his head again, and his gaze seemed to pass through the crystal canopy above his head, "If the human race can survive the next invasion war, the human technological civilization will also usher in a great stride." ”