After Leizi hit the ground, he shouted at us, "No problem! Come down! ”

We glanced at each other and nodded, I went down first, after the Mo Daoist broke off, and after all four of them went down, the 'lid' on it just closed.

"How do you feel a little bit like inviting you into the urn?" Jia Ren looked at the gap above his head that was still seeping water and muttered to himself, I patted him on the shoulder, "Where are so many conspiracies, it's just a coincidence, you look at this flat terrain and a blocked road, how can it not look like there is a mechanism." ”

I learned from Daoist Mo's tone and pretended to give a deep point, Lei Zi smiled secretly in front, "Brother's insight is unique enough, this place really doesn't look like a trap, it feels a bit like a pipe in the sewage system, do you think it's a bit like that?" ”

I raised my head and held up my flashlight and swept around, except for the fact that the whole cave wall was indeed a circle except that it was somewhat flat under our feet, and the green bricks on it had been stained black by moss filth, but according to my understanding, it was more of a large water pipe than a sewage pipe.

"What's the difference?" Jia Ren asked suspiciously after listening to my opinion, and I smiled, "Of course there is a difference, this is the same as if you want to drink water, you have to go to the water pipe, not from the sewer." ”

"Grass! You're going to the sewer to get it from the water! Jia Ren retched, I laughed, and at this time, Daoist Mo, who was leading the way in front, suddenly turned his head and said to us: "Is it possible that there is an artificial canal used for water transportation?" ”

Lei Zi and I were both stunned, maybe he asked a question just now to trick me, Jia Ren now a little bit want to show off, so he tilted his neck and thought for a while and said deeply: "Well, there is some truth, in ancient times, there was no cement, and loess had to be used to build houses, and it is not impossible to get a place like this to transport loess to achieve the purpose if the loess is not enough." ”

"Let's not talk about whether the soil used to burn adobe is the loess above our heads, just using water to transport soil amused me, how can you have such a genius idea? If you were in ancient times, you wouldn't be enough to cut off ten heads as a mason. I smiled and patted him on the shoulder, "It's better to listen honestly to my brothers to popularize your knowledge." ”

Jia Ren was deflated again and could only roll his eyes as much as he could, and Leizi said with a smile: "Stop bickering, we seem to be about to get to the place, you look ahead." ”

A stone door can be seen at a distance of about 30 meters, but the shape of this stone door is a little strange, usually the general door is the upper circle and the lower circle, and the stone gate in front of you is completely upside down, the top and the bottom circle.

"This is weird, and it has a sense of disobedience." Jia Ren shook his head, and I said, "Can you not violate the peace?" Where have you ever seen a door with a circle at the top and a circle at the bottom, which does not conform to the perception and common sense of people at that time. ”

"Oh, I see, you're talking about what people thought was a round place in ancient times, right?" After Jia Ren finished speaking, Lei Zi shook his head, "Actually, the Tianyuan place is just our misunderstanding of our ancestors, in fact, at the beginning, the real meaning of the Tianyuan place is just the sixty-four hexagram azimuth map. ”

Daoist Mo also nodded and said, "Well, the place in the round heaven and the earth refers to the four directions of east, west, north and south, and the people of later generations have misunderstood. ”

I think back to a book I read, which has a very clear commentary on the round sky and the place, in fact, in the Han Dynasty, there was a saying that "the universe is like an egg, and the earth is like an egg yolk".

The "armillary sphere" made by Zhang Heng, an astronomer in the Eastern Han Dynasty, is the "armillary theory" that determines that the earth is a sphere, and his theory believes that the earth is like an egg yolk floating in the universe, and what is even more amazing is the emergence of the infinite universe "Xuanye theory".

"Come on, why are you still taking turns to teach me, I'm not interested, you are so knowledgeable, can you explain what the hell is going on in this subject?"

Jia Ren pointed to the stone gate seven or eight meters in front, I squinted and looked at the way I just walked to the front and wanted to continue to get closer, but Daoist Mo grabbed me in front, "Look at the step." ”

I looked down and saw that there were a few square cracks in the middle of the stone road under my feet, and Leizi walked over and squatted on the ground, and the commander reached out to the gap and turned his head and said: "It's windy, it's empty below, people who step on it may fall down, it should be a trap." ”

There are so many ghost halls, what's behind this door? I squinted at the stone gate, and then at what might have been a trap, and to get into it I had to step on the trap and push it open, and there was no other way.

"What do you say now? Why don't we hang the rope above our heads and learn from Tarzan of the Apes? Jia Ren said, I picked up the flashlight and shone it up, "This curved cave roof has to fall even if ants climb up, and there is no point of focus that can tie the rope." ”

Daoist Mo looked at the ground and thought seriously, I also walked around to see if there were any other secret passages here.

"Hey, that's weird, how can there be footprints on this head?" Jia Ren held a flashlight a few meters behind me and looked at the top of his head and let out an exclamation, I walked over two steps and looked up and couldn't help but take a breath, there were indeed a few strings of yellow mud footprints on the top of the arc-shaped cave.

"Spider-Man?" Jia Ren looked at me suspiciously, and I shook my head, "If I knew what I was doing with you here." ”

After Mo Daoshi and Leizi walked over, they also frowned when they saw the footprints above their heads, if it was a prank that someone put their shoes on top to do it, it would be too idle and realistic, because those footprints looked like they were left by normal walking.

"It still seems to belong to the footprints of three different people, and there are no traces of grasping them with their hands, as if they were left by walking now." After Leizi finished speaking, he took a deep breath and looked incredible.

I followed the direction from which the footprints had come for a moment, and then followed the footprints to the trap, which seemed to enter the stone door.

We didn't find the footprints just now because the traces of muddy water were already very thin, and if it weren't for the footprints in front of us, we wouldn't have thought that they would be footprints at all.

The round door above and below, the footprints above the head... These two things were suddenly connected by some kind of information in my mind, and I carefully peeled back the information I could think of in my mind, and finally came to a terrible conclusion.

Perhaps the space is upside down, or perhaps the place where we are standing now is the real upper part of the passage.

But this idea is a bit fantastical, what is it that allows us to stand on top of the laws of physics upside down?