So, About Those "Ancient Aliens"

So there was this show on Netflix about Ancient Aliens - how there are hieroglyphics and carvings and artifacts and such other evident "proof" that there existed some sort of ancient alien that visited Earth centuries ago to possibly help the ancient Egyptians and Mayans and Sumerians (not in that order, of course) build these amazing pyramids and Stonehenge and likewise places. There is supposedly no way that those civilizations could have possibly built such huge and magnificent structures on their own, including the Nazca lines, which can only be viewed in their entirety from the sky, and the Nazca "plateau", which is thought among many to be an ancient airport for UFO's or whatever they assumed was traveling by flight in that century.

My question - why does this have to be aliens? We know NOTHING about aliens, right down to their very existence. So how are we to assume that, even if they DO exist, that they are some master race that is SO extremely intelligent that they've come to our planet and changed our history altogether? I, actually, do believe in the idea, at least, that there is something else out there, hovering just beyond where our telescopes can reach. I'm not so naive to think that we are the only intelligent life out there. But why could it not have been US - or at least a future us - that helped the ancient and shaped our history - or maybe even changed it...

Time travel.

Okay, so it sounds just as far fetched as aliens but maybe not so much. I mean what if a future American or Chinese or equally advanced society has discovered time travel? Who is to say that they haven't decided to go back in time, visit these ancient civilizations just because we HAVE been curious about them our ENTIRE lives, and say, hey, by the way, use this tool and this tool and this rock and build a pyramid that will have our future generations wondering how in the hell you did it for eons to come. Why not? Maybe they are even links to show us how to invent/discover time travel and we haven't figured it out yet. So when we do, we send ourselves back to show ourselves how to do it. Makes more sense to me than aliens showing up and building rock formations that have no discernible meaning or reason. Stonehenge - really? No matter what any scientist or archeologist tells me, I can't believe that they have any useful existence in today's world other than driving people insane trying to figure out what they mean. The Nazca Lines - animals and random lines in the sand that befuddle archaeologists to no extent. Pyramids - structures built with no obvious purpose but have reason to believe were actually powerhouses that could release vast amounts of energy for POWER.

There are reasons for these things but somehow I don't want to attribute our most advanced of the time, amazing structures to beings that aren't even known to exist. When I see a UFO for myself, yeah, I might change my mind. For now... I guess it's time travel in my book.

Or, ya know, maybe they were just smart old people.