Theory 1: Extraterrestrial Contact

Okay, so, as we all know, mankind has built things before that are beyond our own comprehension.
Take for example, the Pyramids of Gaiza. These pyramids would be hard as hell to design today- much less several thousand years ago with primitive stone tools.

However, these weren't just built over time. They popped up at the same time other monuments such as the pyramids of Maya and temples in Asia.

This can't be a coincidence. When this happened, we still had STONE TOOLS. How they were made would make you think we had gigantic drills and cement trucks, as well as solid steel tools. Something more advanced, obviously not of human origin, had to have helped us.


Theory 2: Extraterrestrial Origins

I've done my research for quite some time now about Africa's Great Rift Valley. What shocks me is the fact the so called "valley" sort of resembles a crash site.

Here's the valley from an over head view:





Here's what it looks like from a human point of view..



Here's one thing that baffles scientists: The fact that this is the BIRTHPLACE of homosapiens. Now, what if we were experiments, or, descendants of an alien race that was on a alien ship that crashed in that location?

Rift Valley also has MASSIVE steel deposits. This also supports my theory, because the ship could've been made of metallic alloy.

As we all know, things that crash leave a mark. If this "ship" was large enough, there's no reason it wouldn't make a crater so enormous.

So, add up the facts and you'll notice why this is my most supported theory.