vision-master wrote:How about pre-Inca?
Doesn't matter. With a stone quarry, harder stone tools, logs, and the labor to do it, any idiot can get a wall like that built 500, 1,000 or 20,000 years ago. All it takes is a group of Homo Sapiens with the will to do it. It doesn't take space aliens.
Anyway, space aliens would, I hope, build a prettier-looking wall and longer-lasting buildings. But I seriously doubt they would build a space program with the intent of building some architecture in South America. I mean what sort of ludicrous goal is that?
Kang: "Hey Kodos, I've got an awesome idea: let's go to Earth and build a cunningly designed wall out of Earth rock so that future Earthings can marvel at it!"
Kodos: "So let me get this straight, Kang: you want us to transport specialized rock-cutting equipment and heavy lifting machines tens of TRILLIONS of Earth miles, land on Earth and start building monuments made out of rock. Then we just fly away?"
Kang: "Yeah, it'll be great! We'll build it on that triangle-shaped continent - the one that's attached to the kinda bowl-shaped one. And we can't use only the straight-cutting tools - we also need the ones that do those neat rounded edges and the ones that make the rocks fit together precisely. It'll be classic!"
Kodos: "Kang, you are such a fricken dumbass!"
Did we go to the moon to build a fricken church or a skyscraper? No, of course not, because our space program is not run by morons. And space aliens wouldn't be that stupid either.
Your problem is that you don't understand Occam's Razor.