In front of Catherine was a thirty-meter-wide underground river. The huge sound of water could indicate the turbulent water flow. There was a corner not far from the underground river channel. A large amount of river water hit the river bank at the corner, splashing water, making the already wet environment even more humid. Just standing on the river bank, the clothes on the whole body could wring out the water. However, standing by the river, the originally stuffy environment was much more comfortable. The water attribute elements significantly reduced the temperature, making the surrounding explorers feel a little reluctant to leave the river bank.

"This is so strange." Panis walked to the shore, frowned tightly, rubbed his chin and said in confusion: "When I was outside this cave just now, did anyone hear the sound of the river? I didn't hear it anyway."

"Huh?" Panis mentioned, and Catherine immediately realized what the inconsistency felt was just now. As Panis said, it was only a tunnel less than ten meters apart, but there was no sound of water inside outside. Even in the tunnel, you could see the wide dark river, and you could not hear the sound of water at all. Only when you walked to the cave exposed by the dark river, the sound of water suddenly appeared: "If you don't say you haven't noticed it yet, you have never heard the sound of water before. Mr. Ike, is it always so strange here?"

"Haha, it really scared you." The guide Ike held his thick beard and his bark-like face filled with a smug smile: "Along the way, you, especially Panis, see nothing strange, at most, just express your surprise, and there is no shock or confusion that you should have when you first arrived here. Now I finally got the chance, hahaha, that's right, this has always been like this, and the sound of water cannot be transmitted outside is the biggest feature here."

"Is there any reason?" Lina played with her long silver hair on her sideburns, her eyes filled with curiosity: "There is nothing special here, is it because of these plants on the shore?"

Originally, except for Catherine walking in front, the shoulder lights of others were not turned on. One was to save the consumption of crystals. Of course, this was just Katherine's opinion, and more because of the second reason. This is different from the crying cave I had been to before. Until now, everyone has been moving in a relatively narrow tunnel. In this environment, just relying on the faint light above the head, you can see clearly all the up, down, left and right positions around you. If you turn on the shoulder light, it will cause interference to the teammates walking in front. Therefore, Catherine, who was opening the road in front, used the shoulder light to illuminate the road ahead alone, and the rest of the people can follow.

Hearing Lina's words, several people turned on the shoulder lights at the same time and looked around. The location of the underground river is an oval cave. The river passes along the longest ends of the oval. The cave is more than 40 meters high, which has exceeded the height of some tunnels on the previous floor. However, due to its location, it does not connect with the previous floor. On both sides of the river, there are many trees that are as high as the top of the cave. The leaves of these trees cannot tell what color they should have, but under the light, they look grayish white and dark purple. Moreover, the leaves are obviously full of metal, and each leaf is crisp and hard. When it falls on the ground, it even makes a tinging sound.

Catherine opened the shield of Dou Qi, walked to a tree tentatively, and knocked on the trunk. As she expected, the trunk was filled with metal elements like the leaves, and it was like knocking on a sword. If there were no fallen leaves on the ground, no one would have thought that they were still alive plants. Catherine pulled out a one-handed sword, poured Dou Qi and gently cut the sword at the trunk. The contact position made a crisp sound of gold and iron clashing, and only a shallow sword mark was left on the trunk.

"Vivian." Catherine picked up a few leaves of different colors and handed them to the mage girl: "Burn."

Vivian pinched a leaf with two fingers, and flipped his wrist and the flames were already burning on the leaves at his fingertips. The fire was far more violent than imagined, and the leaves were more resistant to burning. It took two minutes for the leaves the size of a palm to be completely burned out. Vivian raised his hand as if he was holding something and shook his head and said, "It seems that your idea has failed, sister. This hard material cannot be processed into armor, nor can it be heated and forged. And you see, the residue that flows down after these things in my hands are burned out."

Catherine came up and shone it on her shoulder lamp to observe carefully. On Vivian's gloves, there were black residues, which felt like metal debris. She pinched one and looked at the light for a long time: "Is this metal?"

"This is copper, pure copper." Vivian said: "I have never heard that plants and metals can grow together, but this is true of these trees in front of me. There should be a copper vein deep below them. I don't know how it absorbed a large amount of copper into my body, so it became like this."

"Don't think about it, this cannot be used. We have tried it before." Ike persuaded: "More than 70 years ago, someone took out a few branches and gave them to the goblins to study. The goblins found many scholars from the Magister Guild to cooperate with each other. They studied it for five consecutive years. The final conclusion was that except for burning dry firewood, they had no other value."

"What a pity, I thought I could be made into armor for sale." Catherine was helpless and threw away the leaves, not particularly disappointed. After all, she didn't have much expectations: "Although these plants look very strange, they shouldn't be able to make the sound impossible to convey."

"If it is logical, it shouldn't be possible to grow such trees here. After all, there is no sunshine here." Pannis suddenly drew his sword, and people around him could feel the strange energy representing the power of the domain to his body, allowing him to raise his power to the top, and then cut it on a tree with a sword, breaking it into two pieces from his waist: "If you have no responsibility to guess, I would guess that they rely on absorbing huge sound waves to maintain their lives. The sound here cannot be transmitted outside because they have absorbed all sound waves. I believe they have a unique way to form a barrier at the entrance of the hole, so that the sound waves that should have been penetrated from the hole are reflected back into the hole for them to absorb."

"What do you do to cut it down?" Catherine frowned and looked at the big tree with a diameter of one meter falling down, making a huge sound, and waited until the roar was over and said: "It is true that the sound lasts less than in a normal cave, but when I called you over just now, didn't you hear it too? No, I remembered that I was shouting you at the entrance of the cave and didn't come in."

"Anyway, it's a lie to guess, just guess. As for whether this is the case, I'm afraid no one will know about it in a few hundred years." Panis measured the broken trunk and waved his sword to cut it down again. The demigod's attack power was indeed strong. A sword that looked casually chopped off, cut off a piece of log more than 30 centimeters from the trunk. He lifted the log with his left hand and weighed it in his hand. Panis nodded and said, "As expected, the weight of this kind of tree is actually very light, lighter than solid wood of the same volume. It's really interesting. It contains a lot of metal, but the weight is smaller than wood."

"You want to make something with it?" Lina looked at Panis's movement curiously: "But the hardness is so high that it is difficult to effectively process whether it is chopping or cutting. What can it be made?"

"Apart from chopping or cutting, isn't there any polishing?" Panis smiled mysteriously, tied the stakes with ropes and carried them on his back: "As for what I want to do, keep it confidential first, hehe, you will know when I make it."

Lina glared at him angrily, walked to the river bank, moved the light column of the shoulder lamp to look into the river. The whole river was wide, the water was turbulent, but the river water was very clear, and the smooth gravel at the bottom of the river could be seen through the high-speed flowing river water. Between the gravels, aquatic creatures living in this underground area all year round swim around from time to time. Although the individual size of these creatures is not as exaggerated as on land, they are much larger than their distant relatives in the Yara Continent. Lina waved her hand, and a magical technique to detect toxins was put down at the river water, confirming that there was no toxic component in the water, and then squatted down on the shore, reached into the river water and tried it, frowned and said, "Why is the temperature so high? It's almost as hot springs as the ones soaked in Senaya."

"Maybe there is a gathering point of the earth vein energy with fire attributes on the road you pass, or you pass by the magma pool." Catherine said: "But I suggest you leave the shore first."

"What, did you find the monster?" Lina stood up and shook off the water droplets on her hand.

"Not yet." Catherine shook her head and said, "However, there is a high possibility that there will be lurking monsters in this unknown water. You forgot what happened when we ventured outside the border of the Bailong Dominion in Neville. I don't want to see you being dragged into the water by a monster that suddenly came out, and then almost drowned in the water deep in the chest. Moreover, the water flow here is so fast, I guess you will be washed away soon after you go down, and it's too late to save you."

"Sister, don't worry, I can't forget the lesson." Although Lina said comforting words, she still obediently took a few steps away from the river bank: "Look, if there is such a clear water, if there is a monster lurking in the water, we will never be unable to see it, and we are not blind."

Just as Lina's words were not finished, she just retreated from the river bank, the water surface suddenly exploded, and a blurry shadow, with splashing water and violent sounds, jumped out from the bottom of the river.
Chapter completed!