Deep in the ocean, here and on the surface is a completely different world, perhaps less noisy and quieter, but in those dim corners, there are still many murderous motives.

A huge school of tuna meets several hammerhead sharks, whose scarlet eyes are ready to hunt for food. The schools of tuna quickly gathered together, almost one after the other, and looked like they had become a huge fish.

The first hammerhead shark was launched, and its speed was very fast, and its powerful tail stirred up the water, stirring up the mud and sand at the bottom of the sea, and rushed out like an arrow.

Then the second and the third opened their mouths and slammed into the school of tuna, completely scattering the fish, and the entire sea was stained red with blood.

Fighting, fleeing, countless broken fish scales floated in the sea, flashing and flashing. From time to time, there are broken fins and only half of the tail remaining.

This hunt tends to last for a long time, and the strong smell of blood will attract many more fearsome hunters, whether it is a great white shark, or a ......

A large black shadow slowly moved in this direction, accompanied by a roar that had never been seen before.

The hammerhead sharks were a little frightened, and they were very sensitive to sound waves, and they felt the sound that only belonged to the king whale of the sea. Without the slightest hesitation, several hammerhead sharks turned around and fled. Even if it may be a long time before you succeed in catching such a huge school of tuna, it is far less important to eat than to save your life.

Not only them, but a huge great white shark in the distance also gave up the meal that was about to reach its mouth, and it also saw the behemoth that was getting closer and closer, and after weighing the size, it still chose to retreat.

The speed of the "whale" gradually slowed down, and after passing through the battlefield just now, it finally stopped, as if it was lurking and preparing to hunt.

"Doctor, we're here. In a cold sweat, the commander woke up the doctor who had one leg stretched out from the bed and stepped on the fish and peed, who had obviously not had a good rest for a long time, and was still sleeping soundly in the hot and humid submarine.

"What's going on out there," the doctor rubbed his sleepy eyes, rolled over and jumped off the bed, stretching.

"Well," the commander grimaced, "you'd better see for yourself." ”

The two of them went to the control room and "turned on the active sonar." ”

On the instrument panel, a circle of light spreads out in all directions, revealing a blurred shadow.

"What does that mean?"

"There's a huge hole in front of us, and it's exactly the coordinates you gave. ”

"Turn on the lights. The doctor pulled down the periscope above and put it in front of his eyes. Several strong lights on the front of the U dive and the conning tower were lit up instantly, and the bright pillars of light pierced out, illuminating the surroundings as bright as day.

Hiss~

The doctor took a breath abruptly, startled by what he saw. He slowly turned his periscope and watched the scene around him.

The first thing that catches your eye is a huge hole, and even if the powerful searchlight rays shine through it, you still can't see the scene inside.

And everything around me completely shocked the doctor. A long and narrow wall stretched into the distance, a large clearing where even though it was all silt and coral, the traces of artificial excavation could still be distinguished.

In some places where there is no silt, a piece can be seen very clearly

A huge block of masonry, neatly built and tightly fitted.

In addition, there are some solid buildings covered with seagrass and coral, which can be seen in the traces of pavilions, halls, squares, and towers.

It's like an underground city!

"My God, what is this place, Atlantis? It should be in the Atlantic, too. His excitement was beyond words, he had some information, and naturally had some knowledge about this place, but when he saw these things, he couldn't help but sigh.

There are many legends about the current location between Ryukyu and Okinawa, but there is never a definite record of what kind of place it was.

"Doctor, shall we go inside?" the commander asked, a little embarrassed, although the hole looked large, but it was still a little narrow for the huge U-boat. It's very difficult to drive in.

"To go in, of course to go in!" the doctor's eyes flashed with fanaticism, "We have arrived at God's gate, where is the reason not to go in as a guest?" He actually wanted to go out and have a good look at this magnificent underwater city, but there was no device on the U-boat that could support the undersea walking, and this depth calculation was also close to the design limit for the U-boat, and if they wanted people to go out, it was simply a Grimm fairy tale for them now.

"Keep the active sonar on, and I'll use the steering wheel to assist in submarine attitude corrections, and report any problems to me. "After the commander gave the order, he personally went to operate the spare manual steering wheel and did his best to ensure that there were no problems.

Brody and Olivia were awake, and they ran over, and the doctor proudly showed them what was going on.

"Huh?" Z wondered slightly, "Is this really ...", he didn't continue, and when Brody wanted to ask what the hell this place was, Z didn't move again.

"Double in one! Keep the power to a minimum. "The chief engineer was busy in the hot power compartment, reducing the revs of the two diesel engines to the lowest speed at the time of the submersion, and in this case, the U-boat became a quiet behemoth.

The doctor kept holding the periscope, saying that it was impossible not to be nervous, his sweat had already wet his entire back, and the U-boat slowly approached the deep black hole, and when he got closer, he could feel its horror.

There was no light in it, and nothing could be seen in the depths, no matter how you looked at it, it looked like a monster's open mouth, leading directly to his stomach, and was inviting you into the urn.

The edge of the cave shows some traces of artificiality, including some carvings and masonry, two gateposts that have been eroded by the sea and are almost invisible, one of which has been broken, and many shellfish on the top.

The sonarman, helmsman, and commander were all nervous, and at this time, the slightest mistake could send the U-boat into the rock wall, and if the watertight compartment rupture, no one would even have a chance to escape.

"Slow down, slow down. The commander held the steering wheel in his hand, turning it a little from time to time, and the posture of the U-boat changed slightly in his hand, and even the doctor couldn't help but close his eyes when he saw that the hole was already in front of him.

If you misorient yourself, you will die.

Luckily, there wasn't any impact feeling coming, u

The boat was still moving slowly, and from time to time there was a piercing sound on the shell, which was a coral reef clinging to the doorpost, broken and shattered under the squeeze of the outer armor of the U-boat.

Every second at this time is so long, and the feeling of being cut by the scythe of death at any time is really not so good. The doctor's fingers holding the periscope were already white from exertion, even though he could no longer see anything in the periscope.

The hole is not completely horizontal, it slopes downwards and leads to a deeper bottom. Luckily, however, the cavern space is getting bigger and bigger as the boat moves forward.

But even then, no one dares to take it lightly, the sonar refreshes every few seconds, and the reflected ultrasound constantly feeds back the situation in front to the sonar instrument panel.

It is very strange that such a large hole is not blocked by the silt on the bottom of the sea, and even has a certain flow speed, where exactly does it lead here, this is the question in the mind of every boatman.

"Doctor, if we continue, we may be close to maximum depth. "The commander's voice sounded from the communicator, they had been moving forward for several minutes, but judging by the sonar, it was far from the end.

"Keep diving!" said the doctor without hesitation.

Brody was actually a little scared, he knew that they were at the bottom of the sea now, it was beyond his knowledge, he stroked the walls of the cabin, could these steel plates really block the endless water?

The diameter of the cavern had grown so large that the Commander did not need to continue to make posture corrections, his attention was entirely focused on the manometer, the upper pointer turning steadily and resolutely, telling the people that they were now heading deeper.

The U-boat is not a teardrop-shaped design, and its non-circular shape determines that it cannot dive to ultra-deep depths, and the depth has now far exceeded its maximum depth, and even exceeded the limit depth, and is approaching the design depth.

However, the sonar still did not detect the end.

The Commander panicked, did this road lead all the way to the center of the Earth? or... He was a very old submarine commander, but he had never seen such a strange place at the bottom of the sea, and he had naturally seen the majestic underwater structures before he informed the doctor.

In his opinion, the existence of such a cave can only be a god who can build a city and dig out such a cave in the ocean, and they really want to disturb the god? He ran quickly towards the doctor, and for the first time inside the dim submarine made him feel fear, a fear that gradually went to the unknown.

And at this moment, with a few dull noises, the external searchlight was dismembered by the powerful water pressure, and the bulb was declared scrapped after a few flickering. The doctor finally gave up looking at the periscope that only had endless black, leaning against the bulkhead and clenching his fists firmly, he was also at a loss.

"Doctor, the pressure has reached the red zone, and we may be squashed if we dive any further!" the commander said to the doctor with an ugly face.

"Dive!!"

The doctor looked him coldly into the eyes, and his tone was full of madness.

PS: The performance of the U-boat is not so strong, as I said before, the author will try to get as close to reality as possible, but after all, everyone should think of it as a modernized U29.