"Aliens, dude."

Everyone knows that meme with the stoned-looking historian smiling as he waves his arms in the air. The Ancient Aliens series, which aired on the History Channel, was one of the first television shows to really look into the possibility that humans may not be the only species to have found earth.

Unlike other people who have claimed aliens came to settle earth, the History Channel television series suggested that aliens led to the dinosaurs's extinction. This, of course, is insane. Ancient Alienswas blasted by historians, scientists, and archeologists as psuedo-scientific and revisionist in nature.

However, many people do believe that ancient aliens could have existed and they have some kind of contribution to human history - and sometimes, it's hard to deny something odd is going on.

Truth be told, there are many pieces of archeological evidence and strange mishaps that can't really be explained without some serious questions at hand. Here's some of the biggest arguments for the case of ancient aliens, per those who believe in it.

Alien Statues

Quite a few statues exist across the world that depict creatures that look a lot like grey aliens, astronauts, and other similarly sci fi creatures. The artwork always looks the same, with minor stylistic differences, which makes it even stranger.

The statues and paintings in question always either have heads that look like "space helmets" or large, black eyes and large heads reminiscent of the classic grey alien type.

Most recently, the artifacts that archeologists have found matching this description were discovered in an ancient Mayan city in Mexico. One has to wonder what inspired people to create these works of art, considering that sci-fi wasn't exactly a genre back in those days.

Additionally, the Mayan site in question also had artifacts that apparently depict a flying saucer beaming people up into a ship. Could this be a sign that extraterrestrial visitors actually did come to Earth thousands of years ago?

Ancient Geoglyphs

Geoglyphs are massive works of art that are only visible if you are thousands of feet up in the air. They take loads of planning, and, depending on the kind of geoglyph, could also require advanced technology.

So, how, then, did so many different civilizations create geoglyphs? Moreover, why would they do such things when they themselves would not be able to see the works of art they did? Who were they making these strange marks in earth for? And ultimately, does answer the questions whether of not could ancient aliens really have existed?

Evidence On Mars

For years, the Curiosity rover has been taking amazingly detailed photos of the Martian landscape and sending them back to us. A lot of the photos seem to have things that look like humanoid remains, shiny tubes that come out of the ground, and other eyebrow-raising shots that make us wonder what happened all those years ago.

As of now, scientists are 100 percent sure that Mars used to have more water on it than its current ice caps. However, they aren't sure that there was vegetation or actual life on there. Additionally, if societies lived there, many experts noted that there's not much chance that their technology survived.

Due to the markings left on rocks and other items in the Martian landscape, some scientists believe microbes may still live on Mars - or at the very least, once lived on the planet's surface. We must ask, could ancient aliens really have existed on Mars?

That being said, scientists have also noted that Mars has extremely high levels of radiation at certain points. Though these emissions could be explained through natural means, scientists are beginning to believe that these may have been caused by a war between two factions.

But, if this was the case, where were the cities - and where did the archeological evidence go?

Pyramids, Everywhere

It's kind of fascinating to think about pyramids. Historians aren't quite sure how Egyptians made them - or really, why so many different other civilizations have had them as status symbols.

South American cities had them, Egypt had them, many parts of the Middle East had them, and even ancient China had one or two pyramids that were found by archeologists trying to uncover what life was really like.

Though the pyramids alone don't have anything to do with aliens, people are saying that all of the similarities in the architecture may have something to do with visitors from another planet. Imagine our pyramids were proof that ancient aliens could have existed.

Anachronistic Technology

In Egyptian tombs, there are visible depictions of what appears to be a helicopter and a laptop computer on the walls. There are moments where iron pots have been found in the rocks at Stone Age excavation locations. What appear to be sneaker prints have been found in rocks dated to hundreds of millions of years old.

These discoveries have been so commonplace that they now fall under a category of their own called Out-Of-Place Artifacts, or OOPAs. Who's to say that we aren't just getting a glimpse of some items that visitors may have left behind? Who's to say this doesn't prove that ancient aliens could have really existed.

Even if the anachronism is just depicted in art, it makes you wonder, doesn't it?

The Blunt Truth

While there are definitely some head-scratching moments where archeologists can't explain what's going on, the fact is that the truth is often way less interesting than we want it to be. A lot of this could just be due to cultural shifts, or due to happenstance.