Huo Ling nodded and said, "I'm afraid that's the case!" Human history is only millions of years, and the formation of bone fossils takes tens of millions of years at the shortest! ”

'Ding-dong', Xu Yifan curiously continued to dig down with a small shovel, and in his hot wheel-like waving, he dug down a full two meters deep in a short moment.

Bone fossils, bone fossils, all bone fossils! Countless fossilized bones have been neatly stacked to form a spectacular bone tower.

"I'll you, the two of us are now developed, and we actually discovered a prehistoric civilization, which will be the most explosive news of this century!" Xu Yifan sat on the ground, looked at the spectacular bone tower in front of him and said with emotion.

Huo Ling said, "Let's take a look at the other stone chambers!" ”

When he came to the stone platform in the southeast corner, Xu Yifan just wanted to raise his fist and bang, but was stopped by Huo Ling.

"No need, I'll just feel it!" The fire spirit said as he looked at the tiny stone crevice.

After a while, Huo Ling stood up, nodded at Xu Yifan and said, "It's all the same!" ”

"I'm curious about what's inside the biggest stone platform in the middle!" Xu Yifan scratched his head and looked at Huo Ling and said.

The two of them circled around the giant stone platform in the middle twice, Huo Ling looked at Xu Yifan and shook his head, "The seal is too tight, my perception can't get in!" ”

"Boom, boom, boom!" After three bangs, the stone door was finally violently opened by Xu Yifan, and a cold wind poured out in an instant, making the two of them shudder!

"Be careful, this isn't supposed to be a sealed stone chamber, maybe somewhere!" Xu Yifan grabbed Huo Ling, who wanted to go in, and said.

"Are there any candles?" Xu Yifan asked.

Huo Ling nodded and said, "Are you afraid that there will be a lack of oxygen inside?" ”

"It's not just a lack of oxygen, I'm afraid of poisonous gases in it!" Xu Yifan said seriously.

Huo Ling nodded thoughtfully, thought for a while, and said, "In this way, let's tidy up the backpack first and see what can be used!" ”

After sorting out, all the electronic equipment such as air quality analyzers, miniature electronic remote sensing imaging aircraft, etc., were taken out and were still outside the door.

The two of them hung a high-compressed oxygen mask around their necks, held a multi-functional alcohol lamp in their hands, and slowly walked inside with backpacks on their backs.

Huo Ling even took out a folding rapid-fire machine gun from his bag and hung it on his side, and took out a few magazines and inserted them in his waist.

The height of the hole made of bluestone is three or four meters, and the width is nearly three meters, except for the cool wind, it is still relatively dry.

The two of them walked slowly down the bluestone steps, which were steep and deep, and walked a long way.

"I'll go, Sister Huo's hole seems to be very deep, we almost walked a thousand meters, right?" Xu Yifan said with a sigh.

"Yes, the vertical distance is not less than 800 meters!" Huo Ling nodded in agreement.

Turn around a gentle turn.

Suddenly, the width increased to twenty or thirty meters, and the height was due to the light, and the top could not be seen due to the light! And there is still endless darkness ahead.

"I'll go, what is this place, I'll go, what is this place, I'll go, what is this place......" Xu Yifan's voice was constantly refracted in the secret passage.

Xu Yifan frowned, and looked at the ground, walls, and top of the secret passage with an alcohol lamp.

Under the radiation of the faint light, the mirror-smooth floor, walls and top appeared in front of Xu Yifan's eyes, "I said why is this echo so clear and long!" ”

Huo Ling tugged at the corner of Xu Yifan's clothes behind him, and said softly: "You take a closer look at the inside of the wall!" ”

Xu Yifan was stunned for a moment, and then came to the side of the wall with an alcohol lamp to observe carefully.

With the radiation of the faint light, obscure inscriptions and patterns flashed in the smooth entry wall.

Gently touched the wall with his hand, without any sense of stagnation, Xu Yifan was sure that these flashing patterns should be embedded dark lines, not carved bright lines!

He tapped it lightly twice with his hand, but there was no sound, the wall was very heavy, like metal but not metal, like jade and not jade, and it was not made of any material.

"Sister Huo, look at it, this skill is not only available in our human society in the past few hundred years! Look at the material again, tsk! Xu Yifan said with emotion.

Huo Ling also nodded, and said while gently rubbing the wall:

"This dark pattern should not be used for decoration, it is more like a rune formation in ancient Tang Dynasty, this material is not deformed or corrupted after hundreds of millions of years, and it must be much more advanced than the most advanced alloy today!"

"Then do you think those monsters that could be invisible before are the remnants of prehistoric civilizations? Heck, if that's the case, they shouldn't all be killed, so they should be left alive! Xu Yifan said with some annoyance.

"Have you ever thought that they weren't a prehistoric civilization at all?" Huo Ling looked at Xu Yifan and asked seriously.

"You're saying they're an alien civilization?" Xu Yifan asked with wide eyes.

Huo Ling nodded first, then shook his head and said, "I'm not sure, but no matter how you look at it, the IQ and combat power of those invisible monsters don't seem to be directly proportional to the information content of this secret passage!" ”

Xu Yifan nodded: "Don't worry about these for now, anyway, there will definitely be professionals who will come to explore and study later!" ”

"Shall we go inside?" Huo Ling swallowed his saliva and asked with some hesitation.

Xu Yifan pretended to look forward with the lamp, looked back at Huo Ling and said: "Sister Huo, it's all here, if I go back now, I'm really unwilling, or you wait for me here or above, if there is any change, you will run back!" ”

Huo Ling looked at Xu Yifan's eyes and shook his head, "Let's go together, wait for me to perceive it!" ”

"It's straight within five hundred meters, and the layout is the same as here!" Huo Ling opened his eyes and said.

——————————————————————————

The sound of crisp footsteps echoed in the empty pavilion......

"Go on!" Huo Ling's voice.

......

"Go on!"

......

"Ahead, five hundred meters ahead!" Huo Ling said with a sigh of relief.

Xu Yifan nodded, "Sister Huo, you rest here, recover your strength, I'll go to the front and take a look." ”

Huo Ling watched the distant points of light and figures gradually become smaller, and her heart was nervous, fearful, and expectant......

"Huo, Sister Huo! Come on, come and see! Xu Yifan's shouts kept echoing in Huo Ling's ears.

Huo Ling was a little excited in her heart, and when she hurriedly stood up, she actually knocked the alcohol lamp to the ground, she took out a military flashlight, and ran towards the end excitedly......