Longyou cave

Was he the same Feng Ye Isey from her previous life? She wondered. However, she still calmly explained to him.

"You see there?" She pointed towards the mountains.

"It's a southern continent mountain range that shares its border with Guangxi. Thanks to it, Guangxi always has a steady supply of water from the Guangxi river. To be exact this is a mountainous river, but have you ever wondered what a cave is doing in the middle of a mountainous river?"

Ye Isey shook his head.

Qin Ru's expressions were normal. It was as if she knew he wouldn't know. "That's because that cave is manmade."

She dropped the bomb.

Feng Ye Isey shook his head vigorously. "Impossible. Although I did not live here for a long time, but I knew it isn't man-made. The cave is here for several decades."

"Just because it is here for several decades does it prove that it isn't man-made?" She retorted back.

Feng Ye Isey was rendered speechless.

"But…. How can you be so sure it is manmade?" He questioned back. He was not ready to believe that the cave was man-made.

"Natural caves are found to be made up of a kind of rock called dolomite. It is similar to limestone. Like limestone, dolomite is formed at the bottom of the sea. Forces from inside the earth pushed up the sea bottom to make the Ozarks. These forces, pushing up on the rock layers, cracked the dolomite. These cracks are called joints. This is the very start of a natural Cave. As rainwater fell on the ground, it picked up a small amount of acid from the rotting leaves. This acid, called carbonic acid. This acidic water can dissolve holes in dolomite. Below the water table, the rock was filled with this acidic water. Between the layers of rock and inside the joints, the water slowly dissolved away the rock. This makes a large water-filled space. Any natural underground river will cut its river valley, as it cut down through the rock layers until it opened up the cave. This lets the water out and gives us an air-filled cave."

"Water from rainfall moves into the cave. A small amount seeps through the rock. This seepage gets filtered as it comes down. It is clear, but not always pure water. Most water that enters the cave comes down through the joints, which connect the cave with the surface. Where there are many joints, sinkholes can form on the surface. Sinkholes act like funnels, collecting rainwater from the surface and funneling it into the cave."

"At some caves, joints leading down from sinkholes have become so big that people can enter the cave through the sinkholes."

"Sometimes, a cave can pirate water from a surface stream. a cave may take water away from a surface stream. If a stream crosses a joint, water may flow down the joint and into the cave. On the surface, water may be flowing down the stream, and then just disappear. This is called a losing stream. Like sinkholes, a losing stream usually means that There is a cave nearby. All of this water that enters the cave has to go somewhere. It is no surprise that many caves have springs flowing out of them. Caves are not cut off from the rest of the world. Many have a constant flow of water moving in and out of the cave all of the time. This water carries the clay, which becomes cave mud. This is natural."

Qin Ru emphasised "A veil of darkness cloaks the natural beauty of caves. Some are found in cliffs at the edge of the coastline, chipped away by the relentless pounding of waves. Others form where a lava tube outer the surface cools and hardens and the inside of the molten rock drains away. Caves even form in glaciers where meltwater carves tunnels at the beginning of its journey to the sea. All these are natural caves."

"However, nature is beautiful while humans are ugly. Anything made by humans has faults in them no matter how flawless it appears. Those caves are man made caves because it's outlet is the same as one of the caves in eastern province. Longyou Caves of eastern province, is a complex of 24 artificial caves, constructed into the sandstone geology of Fenghuang Hill. Do you know what is so special about this cave?"

Feng Ye Isey shook his head.

Qin Ru laughed softly.

"The caves were discovered by accident when a local farmer drained several ponds revealing five large man made caverns and 19 smaller caves. The five caverns, independent from each other measure between 18-34 meters, reaching heights of up to 20 meters with supporting pillars and distinctive shapes remarkably curved with shaking imprints across the cavern walls and ceilings. It was found that each complete cavern has only one portal, associated with a vertical shaft with a carved stairwell that allows rainfall and surface runoff to enter the caverns. To manage the water intake, a system of drainage troughs, some drainage channels, and a water trap was carved into the cavern base to collect the water."

"The caverns are also aligned along south to southwest orientation, maximizing the use of sunlight to illuminate the interior, with inclined sidewalls that reduces the stress on the cave ceilings preventing collapse. It is highly possible that the cavern was formed by carving rock stones from top to bottom and layer by layer using short chisels with different sizes."

"No one knows who the creator of them was, but it was an extraordinary piece of art of architecture. The one who constructed it can be considered as a genius. Of all of the mysteries around the caves, perhaps the biggest is figuring out just how they were constructed. What perplexes experts is this project of extensive magnitude was never documented and no tools were ever found on-site. This is particularly puzzling when you consider how good the makers were at documentation."