"Mr. Cat, you are now 32.78 kilometers away from the Cherome probe in a straight line." Mai Dong stared at the data on the screen, "The direction is correct. ”

"32.78 kilometers in a straight line? But the actual distance traveled is probably more than 30 kilometers. The old cat replied, "If you want to go down, I'm afraid you'll have to take a detour." ”

Mai Dong and Tang Yue were stunned.

"Detour?" Tang Yue got up and typed on the keyboard, and sent an email to ask, "Is something stopping you?" ”

Mai Dong also asked, "Is it a sand dune?"

"It's a sand dune, and it's a continuous sand dune, I parked the Martian stray dog under the dune to recharge, but the slope of this dune is too steep, it has to be as high as a story or two, I don't think the stray dog can climb over it, so I have to take a detour." The old cat replied.

"How far is the detour?"

"I don't know, I'm trying to climb the dunes, and if I stand on a high place, I might be able to see around and see if I can find a way......," said the old cat, "and it's amazing, it's not sand, it's rock." ”

"Rocks?"

"There are rocks buried under the sand, very large rocks, one piece can weigh tens or even hundreds of tons, I think it's basalt, they may have been the product of a volcanic eruption more than a billion years ago, and then the wind erosion has become what it is today." "I've climbed up and let me see where I'm going...... Hell, it's not a dune, it's a wall! ”

Both in the channel were taken aback.

"Walls?"

"It's just a high wall of rocks, it's completely buried by sand, so it looks like a sand dune, but when you dig up the sand, you can see the rocks underneath, layer upon layer, like bricks." "As I stand here, I can see it stretching into the distance, disappearing into the horizon, and I can't calculate its length...... It's amazing. ”

"Like the Great Wall?" Mai Dong asked.

The old cat nodded, "It's like an ancient Great Wall, can you imagine a Great Wall on Mars?" ”

"Is it man-made?" Tang Yue asked.

"It's not necessarily man-made, and although it looks like the work of some kind of intelligent being, it's also possible that it's the result of glacial activity, where ancient glaciers carried rocks, so these boulders piled up along the edge of the glacier, and the work of nature sometimes far exceeded that of human hands." The old cat shook his head, "Do you know the Giant's Causeway in Northern Ireland?" ”

"What's that?" Tang Yue asked.

"A very peculiar landscape, located on the Atlantic coast of Northern Ireland, with more than 30,000 stone pillars of uniform size and regular shape, closely arranged into a stone embankment, stretching for thousands of meters, each of which is a regular hexagonal shape that looks as if it was artificially hewn." "But this is actually a natural formation, the material of the Giant's Causeway is basalt, which is formed by the sudden solidification of lava from volcanic eruptions and seawater, and the reason why the stone pillars are hexagonal is because of the crystal structure of basalt...... So the high wall we see on Mars is also likely to be a natural landscape. ”

Tang Yue is right to think about it, the possibility of natural formation is greater, the action of wind erosion and water flow can sometimes form amazing miracles, how can there be artificial landscapes on Mars?

"I'm walking along this wall, it's over nine meters at its highest point, almost three stories high, you know what reminds me of that?" The old cat is waiting for the rover to recharge, so he is also happy to tell Tang Yue and Mai Dong what he has seen.

"What?"

"Beacon." The old cat replied, "If you think of this wall as a product of a civilization, then this wall is very functional......"

The old cat leisurely searched for clues on the ancient wall, which had been blurred by a long time, but the old cat used his extraordinary imagination to begin to depict it wantonly.

"I saw beacons, and at intervals there were such high platforms, which were perfect for lighting wolf smoke, and the slopes to ascend the walls, the narrow ones that might have been for men, and the wide ones that might have been used for loading and unloading siege equipment...... Oh, and the ruins of the watchtower, I saw a very regular square platform, obviously this place is used for stationing troops, if there is an attack from outside, the soldiers who live here can go out to meet the enemy......" The old cat said and lowered his voice, and finally was speechless.

Mai Dong and Tang Yue had long since stopped talking.

"Damn...... the old cat was stunned for a long time, "is this really natural?" ”

No matter how clever nature is, it has the ability to pile hexagonal stone pillars into long embankments, and it has the ability to cut rocks into high walls, but it will not make you with beacons and watchtowers.

The old cat was shocked.

"Cat...... Mr. Cat......" Mai Dong whispered, "you...... Standing on the ruins of an ancient civilization, perhaps? ”

"No, no, no, no! No way! That's impossible! The old cat shook his head, "There has never been any intelligent creature on Mars, let alone any civilization!" Do not be misled by what I have said before, what I have said can arise under certain circumstances due to natural conditions...... Hell, what is it? ”

"What did you find again?"

"Ditches, long ditches, on the other side of the wall, there are ditches, deep ravines dug along the wall." The old cat frowned, "What did you think of?" ”

"Moat?" Tang Yue is a spirit.

"It's like a moat, indeed, but who can dig a moat for the Wall? The gullies have now been filled with sand, and I have tried to dig them...... "The ditch is about four or five meters wide, the depth is not clear, but it must be at least one meter or more, and the length of the ditch is about the same length as the high wall, and there is no end in sight." ”

Tang Yue and Mai Dong were shocked.

A high wall with no end in sight, placed on the earth will be a world-famous huge project, how can anyone dig a moat for this wall?

"This ditch is also a natural phenomenon?" Tang Yue asked, "Glacier formation?" ”

"Possibly, of course it's possible! The remnants left behind after the melting of the glaciers, coupled with the erosion of flowing water...... "the old cat searched his stomach and searched for a reason, wondering if there was a precedent on the earth, a moat formed under natural circumstances."

But it didn't find.

When you take all the assumptions out of it, no matter how incredible the one that remains, it will be true.

The old cat sat down on the sand dunes, looking out at the high wall winding in the wind and sand, stretching out into the distance, and it did not know whether it was a masterpiece of nature or the legacy of some ancient civilization, if it was really the work of intelligent beings, then there was no doubt that it would be an incomparably brilliant civilization.

What kind of civilization would build a wall across the world on its planet?

The old cat only saw the ruins, but it is not difficult to imagine that when this high wall was built, it must have been a miracle to the sky.

The old cat has no way of knowing the truth, and its database does not contain any relevant information, but it can deduce that in the dark night before the birth of human beings on Earth, the civilization on this planet may have established a great spectacle that shocks people, and in the long time to come, although the civilization perished, these miraculous creations still stand.

"It's a pity......" the old cat sighed.

"Do you regret the disappearance of this ancient civilization?" Tang Yue asked.

"No, I'm sorry that the Earth is gone, and the Mars program is interrupted." The old cat said, "Otherwise, wouldn't it be a lot of money to develop tourism here?" ”