Chapter 459

They continued swimming along the passage in the karst cave. After passing one stretch, Lu Ao noticed that the terrain beyond the cave seemed to be rising. The farther they swam, the more they realized the water level here was dropping.

This was an utterly unbelievable thing, because they were on the seabed.

Logically, seawater should have flooded into any kind of karst cave, yet strangely, no seawater had poured into this one.

Lu Ao thought about it for a long while before he figured it out. This might be a karst cave inside an undersea mountain peak. The passageways below rose and fell, and certain sections were higher than both sides, preventing seawater from flooding in.

They traveled through the cave and swam several hundred more meters. There was less and less seawater in the passage until Lu Ao could no longer swim. He changed back into human form and walked forward hand in hand with Song Zhou.

"This is way too strange. I never imagined there could be a place like this beneath the sea."

Song Zhou shone his flashlight around. "The world is vast, and anything is possible. Let's walk slowly. It's too damp here, and it feels like there isn't much oxygen either."

"It's fine. I can hold my breath pretty well now. Holding it for ten-odd minutes won't be a problem." Lu Ao said, "I think this karst cave probably formed when this place was still above water. I saw traces of erosion from flowing water."

"Maybe. Let's keep going and take a look."

The two of them continued forward hand in hand. After walking for over half an hour, through the cave's rising and falling paths, Lu Ao felt that they had first climbed upward for a long way, then descended for another long