"Cement?" Han Dong looked confused: "Where did this cement come from?"

"The ancient Romans used cement two thousand years ago, this is not a stone mound, this is an entrance closed by cement!" Li Huan became excited and threw away the stone in his hand.

The Roman Empire is long gone, but the architecture of the ancient Romans has stood the test of time. Some of the buildings left behind by the Roman Empire were able to withstand the impact of the waves for thousands of years, and a new study has uncovered the mystery that the ancient Romans had already begun to use cement.

Pliny the Elder, a first-century Roman writer and admiral, described the cement used for the construction of the harbor as follows: "As soon as it comes into contact with the waves and is immersed in the seawater, it becomes a monolithic stone, indestructible against the waves, and grows stronger every day." ”

Modern scientific research has found that ancient Roman cement was often made from a mixture of volcanic ash, rock, and lime, causing it to become stronger in ports and docks when exposed to the impact of waves, compared to modern cement that is very prone to cracking. By studying ancient Roman cement samples and conducting various tests, scientists found that the chemistry between cement and seawater was a key part of their previous studies that they had overlooked. When seawater passes through tiny cracks in the concrete, it reacts with the pozzolanic components of the concrete and produces a substance called aluminum-bearing snow poilicate, which is what made the cement of ancient Rome stronger the more it was eroded.

But apparently, this building in the Gobi Desert was not so lucky, there was not a drop of sea water except for the boundless sand, not only was there no seawater reinforcement, but there were also strong winds. If the wind in other places is just like wiping the building with a cloth, then the weathering effect of the wind and sand here on the building is to use an iron brush to brush desperately, even if the building is hard, it can't resist such a desperate brush for a long time.

It's like this stone mound, it may not have been a stone mound at first, it was something else, but after thousands of years of wind and sand, it finally became a bare stone mound. In ancient Rome, there was definitely no tofu slag project, and those who dared to do tofu slag projects were thrown into the Colosseum, but no matter how strong the construction was, it could not withstand continuous polishing, so this seemingly hard mountain was actually fragile.

In order to prove his conjecture, Li Huan circled around the stone mound, and sure enough, in many places, a piece of weathered cement could be rubbed off with his hands......

Li Huan completely let go of his spiritual power and probed his spiritual power into this huge stone mound...... A minute later he smiled, this stone mound, it was hollow.

Judging from the situation of the spiritual exploration just now, Li Huan can even guess the origin of this stone mound - this used to be the entrance to the pipeline, the ancient Romans were defeated and expelled at that time, probably in line with the principle that we can't enjoy it, otherwise we will enjoy it, before retreating in a hurry, the entrance to the most important water source pipeline was closed with cement, wanting to turn this piece into a dead city.

But who knew that the ancient city, which was rich in groundwater resources, had survived tenaciously to this day, and this pipeline could be used as a place to hide illegal wealth...... However, this entrance has not been opened for thousands of years, and if there is wealth hidden in the underground water pipes, where did Mulaha get in?

Li Huan thought about it, he couldn't care about this.

It is none of his business where Muraha got in, look at the time, there are still 7 hours of dawn, and this underground pipeline must be found within these 7 hours. Li Huan thought about it, this stone mound was so fragile that it couldn't be opened by violence, and he once again used his spiritual power to find out all the vulnerable points and possible collapses

Patience uses a jet of spiritual energy, slowly cutting at the bottom of the stone mound.

In such a harsh situation where collapse is at any time, the only way to avoid rapid weathering is to open the entrance to the lowest place, and it can also keep the entrance hidden for a long time.

Under the aura jet, soon, a piece cracked under the stone mound, because the aura jet had excellent cutting ability, basically no vibration, after cutting about a meter thick stone, a dark hole was revealed. Li Huan probed to feel it, and suddenly a sullen air rushed to his face, Li Huan inadvertently took a breath, the smell of corruption and dampness almost made Li Huan go away, which showed that there was indeed a passage below, but the control quality inside was obviously extremely poor.

A few minutes later, a passage that could accommodate one person to bend down and climb into it was pulled open by Li Huan, who took a strong flashlight and shone it in, and found that the passage behind the cave entrance was very spacious, and it was a downward slope, which should lead to the water pipeline network.

Li Huan groaned for a while, tore off a strip of cloth from his clothes, lit it, and threw it into the entrance of the black hole, the strip of cloth floated less than a meter, and it went out with a hula.

"If you don't have breathing equipment, don't go in with you, it's not that I don't take you with me, it's that you can't breathe when you go in. Li Huan turned his head to look at Han Dong: "This kind of confined space is obviously more dangerous than if we go to Bellamy's treasure cave, if you don't pay attention to taking a breath, there may be danger, your qi practice level is low, and the breath-holding time is not long, so don't go." ”

Han Dong looked remorseful, but he also had to admit that what Li Huan said was right.

This pipe network system may have been opened a few years ago, or Li Huan guessed wrong, it has not been opened for two thousand years, and the ghost knows what is in the air. So even if Han Dong was unwilling, he had no choice but to help Li Huan guard the door. And Li Huan took a few deep breaths, put a layer of spiritual power shield on himself, and then got into it.

After entering the stone cave, Li Huan suddenly let out a burst of admiration: "The ancient Romans have something......

Ancient Roman architecture is a pearl in the treasure house of architectural art, which carries the architectural style of ancient Greek civilization, highlights the characteristics of the Mediterranean region, and is a development of ancient Greek architecture. Ancient Rome became a Mediterranean power in the 2nd century BC, and at the same time the Romans began construction of Rome.

By the time the Roman Empire was established in the first century AD, the city of Rome had become a world city on a par with the city of Chang'an in the East, and its urban infrastructure construction had been relatively perfect, and the city was gradually developing in the direction of art. Roman architecture is very different from its sculptural art, and is famous for its symmetry and grandeur.

In the eyes of architects and historians, the greatest engineering achievements of ancient Rome were not the majestic Colosseum or the tall triumphal arches, but the intricate, scientifically designed, and various aqueducts that could not be integrated at all - as the city continued to grow, the Romans began to build elevated aqueducts almost all over the empire, the oldest in Rome dating back to 312 BC. It reflects the strength of the Roman Empire, and at the same time, the common design method is a great innovation in mechanics and art, saving a lot of materials.

This underground water pipeline is a very typical Roman building, it extends almost horizontally, more than three meters high, and the width reaches four meters.

It's really hard to imagine that in the depths of the desert, it can be repaired

Build such a huge man-made project.

These stone bricks are carved and spliced with a whole piece of stone, mixed with cement joints in the middle, and there are no cracks at all. The stone tentacles are cold, and even a little slippery, it seems that there is still water passing through this waterway from time to time - but where does the water come from? Li Huan used a strong flashlight to shine around, and quickly found the secret, when he understood the working principle of this waterway, Li Huan was even more sincere admiration for the wisdom of the ancients.

To put it simply, it's a fully automated waterway.

In the wall of the water pipeline, there are some large and small holes, Li Huan shines into them with a flashlight, and there is thicker moss in those holes - in the desert, the groundwater also has a water level, whenever the water level rises, the groundwater will automatically pour into this pipe through these small holes, leaving it in the direction of the pipeline design, and when the groundwater recedes, the water will naturally be lost, and it is convenient for someone to come in and clean the pipeline, the person who designed this water pipeline is a genius - I just don't know where it leads, maybe it's an ancient city?

Li Huan turned on the flashlight and walked slowly inside, saying to himself as he walked: "Walking in this place really has a feeling of time traveling...... But maybe I'm wrong? If the water rises and falls, then Muraha must have been washed away even if he moved things here, right? But if he didn't put things here, where did he put them......

Li Huan walked forward while chattering, and walked deeper and deeper, and actually walked out of a distance of six or seven hundred meters. However, when he was almost 800 meters away, Li Huan let a door block the way.

No, it can't be said that this is a door, this is just a pure alloy without any gaps. The door could still be opened, but it was a piece of solid alloy that got stuck in the water pipe, blocking the front. What kind of operation is this? Li Huan tried to use mental power to infiltrate the inspection, but the result was very disappointing, this was really a solid alloy steel.

But this discovery made Li Huan happy.

The appearance of this "door" means that in recent years, someone must have been here, and this solid alloy steel that is more perverted than the underground vault of the bank is used to close the road, and there must be something hidden behind it.

Li Huan told Han Dong about this on the walkie-talkie.

"Brother Huan, what are you waiting for, get out of the way!" Han Dong said excitedly when he heard that Li Huan had made a discovery.

"You get it. Li Huan's face darkened: "This thing is a piece of pure alloy, more than a meter thick, so get it?"

"There are still explosives in the car...... Han Dong just finished speaking, and he smiled: "You can't use explosives, huh?"

Nonsense, of course not, there are still a lot of C.4 in Li Huan's virtual space, but using this kind of thing in this environment, what is the difference between that and looking for death, besides, whether C.4 can blow up this piece of alloy or two, even if it can be exploded, I'm afraid that the entire passage will have to collapse, that's no different from not blowing up this door, I don't know if I have to be buried inside.

What to do?

Li Huan, who had never encountered such a problem, was completely numb at this time.

Don't look at his plug-in, but the problem in front of him is not something that can be solved by plug-ins. This kind of "gate" was designed to prevent outsiders from entering, and to open it, it was necessary to use violent means, and it was a large-scale violent means - whether it was bombed from the top down, or from the inside out, anyway, no matter how you bombed it, the movement must be so loud that people within 10 kilometers could hear it.

What to do?