After smoking three cigarettes in a row, Hu Xiaodao felt that the sand and dust under the water had calmed down.

After getting dressed, Hu Xiaodao did not put on his backpack, but carried the sapper shovel behind his back, took out the paratrooper rope and tied it to the backpack, and tied a small stone to the other end of the rope.

The length of this paratrooper rope is 30 meters, which should be enough, unless the idea is particularly memorized.

What Hu Xiaodao has to do is to empty the air of the backpack so that it is not buoyant, and dive forward with a rope, which must be much faster than carrying a backpack in terms of speed.

To put it bluntly, I am afraid that I will not have enough oxygen in my body.

For example, now this passage is of unknown length, let's say at eighty meters. Let's assume that Hu Xiaodao can only hold his breath and swim for 60 meters.

Then the remaining twenty meters of Hu knife will definitely drown.

If there is a buffer of thirty meters, the chances of survival are greatly increased.

If you are carrying a backpack, your own weight plus the resistance during diving, it is estimated that it will be difficult to reach 30 meters, let alone 80 meters.

Of course, this is just a simple example, Hu Xiaodao after accurate calculations, he felt that he could swim more than 60 meters before he dared to make a decision, if he didn't have two brushes, it was better not to take risks.

Here, Hu Xiaodao also specially instructed the people in the live broadcast room not to imitate him. He would do this kind of thing because he had a full grasp of survival, and he resolutely did not recommend the audience in the live broadcast room to blindly follow the trend.

Although people should have the spirit of adventure, life is the most precious after all, and everyone has only one life.

Dragging his backpack to the old place of the wooden stake, Hu Xiaodao was not in a hurry to go down.

He first grabbed the stake and slowly calmed his mood, and it was not until three minutes later that his breathing slowly accelerated, allowing his body to absorb oxygen quickly.

One way is to pinch your nose and take a few deep breaths, and then inhale again when you feel the oxygen all over your body, and you can't exhale until the oxygen is all over your blood, and the dive time will become longer.

Of course, the fact that ordinary people have not received special training is very fatal.

"Whew! ~”

Without any words, Hu Xiaodao and the others suddenly dived into the water after the oxygen in their bodies was completely saturated.

The backpack in his hand had already sunk to the bottom of the water, and Hu Xiaodao just took the rope and quickly swam through the hole, but he didn't have time to manage the backpack at all.

Crossing the entrance of the cave with the help of the miner's lamp overhead, Hu Xiaodao found that the specifications here were almost exactly the same as those behind him, but there was no wooden stake erected behind him.

This is good news for Hu Xiaodao. Although it is not remarkable at all, Hu Xiaodao can analyze a decisive information.

As we all know, mine holes are generally more than a few hundred meters deep, and the frame is dug a little bit to build a little bit, and the distance will not exceed about five to ten meters, otherwise there will be a danger of collapse.

And now Hu Xiaodao didn't see the bracket made of wooden stakes at all, so there are only two reasons, the first is that it was corroded by explosives or water sources, and there is no trace at all.

This is certainly untenable, because no matter how much it corrodes, it is impossible to completely corrode the wood in a few decades, and you must know that there are countless shipwrecks in the river for thousands of years, and there is no corrosion.

The second reason is that there is no scaffold built here at all, but it has been almost twenty meters since Hu Xiaodao swam over, which is obviously a bit unscientific.

But in an instant, Hu Xiaodao understood that the terrain here was gradually rising, and it should have existed in the original - a natural cave!

With this thought, Hu Xiaodao waved his arms excitedly, accelerated forward, and the rope in his hand suddenly tightened, and Hu Xiaodao spread his hand and swam about ten meters.

"Whew! ~”

The head is full of water and comes to the surface, and I don't feel it underwater, but I just drill into a hole.

When he surfaced, Hu Xiaodao found himself in a circular pit with a diameter of about 70 centimeters, about 40 centimeters from the ground, but the strange thing was that there were two wooden planks across his head, and he didn't know what it was for.

The two planks looked like cedar trees, and they only spanned the entrance of the cave like small bridges, and did not completely cover the entire water hole. It's not like a lid, and although I don't know how many years have passed, it's impossible to have only two pieces left here.

Hu Xiaodao took a breath, dived back to the bottom of the water, grabbed the rope and pulled it over hard, and resurfaced again.

With a slight leap of his body, he grabbed the edge of the hole, sucked it up, and pushed away the wooden plank and the knife was considered to be safely ashore.

Holding the rope in his hand, Hu Xiaodao briefly looked around, this was a separate room and there was no danger, and then he turned around and fished his backpack out of the water.

After putting on the backpack, Hu Xiaodao found out when he was looking for a way out that there were five more holes in the same hole here, a total of six!

How so...... It's like a modern toilet QAQ~~~

This thought only flashed in Hu Xiaodao's mind, and he would not tell the audience in the live broadcast room where he came from, this did not exist at all.

There is a stone wall on the left, and behind the stone wall is a road, and there seems to be light.

Hu Xiaodao turned off the light, and sure enough, there was really light here! But who dug up such a place at a depth of 100 meters and built a toilet? There's still light outside.

Hu Xiaodao put away the paratrooper rope and put it back in his bag, put his backpack on his back and walked behind the wall.

In addition to the "toilet", Hu Xiaodao was instantly shocked by the scene in front of him!

An extremely large cave appeared before his eyes.

According to telescope ranging, the length of the cave is about 1,400 meters, and the width has reached 750 meters, and the height is not so exaggerated, only about 90 meters.

In the middle, there are hundreds of strip stones of about ten meters erected in the center of the hall of the cave, in the middle of the layers of strip stones, a seven-layer round boulder is trapezoidal, a circle from large to small, neatly located in the center of the strip stone, the appearance is similar to the seven-layer cake.

The top is dome-shaped, but there are numerous circular holes about 50 centimeters in diameter, which serve as vents throughout the roof of the cave, and also provide a good visual effect for the "cake" shaped building in the middle of the cave.

The surrounding walls were painted with white, dark red, and black oil paintings and reliefs, and Hu Xiaodao walked into the closest one to take a closer look.

The painting is about three meters high, and the face and open tunic are dark red, the clothes inside are black, and the rest of the painting is white.

The figure is wearing a helmet, holding a spear painted red at the top, holding a shield in his hand, and barefoot.

The background of the whole mural is black, but there are many red eyes looking at the person in the painting on the black background. It doesn't seem like a human eye.

Hu Xiaodao understood that this was a technique of narration by the ancients, expressed through murals, for future generations to observe.

He continued to the second one on the left, and opened the miner's lamp above his head to take a closer look.

This one is much simpler, the background has been changed to white, a native in a sacrificial robe stands in the forest, and a dozen or so people like the one in the first picture are clustered behind the aboriginal sacrifice, and the Black Forest has also become a white relief.