10 Craziest Alien Conspiracy Theories

From exchanging aliens for humans to making UFOs causing disappearances of airplanes, we take a look at the 10 craziest alien conspiracy theories.

We have no proof that aliens exist and despite NASA's claim that we'll have discovered extra-terrestrials before 2040, the fact remains we're getting no closer.

Of course that hasn't stopped us from creating the our own theories, whether it's that we're all just being observed like zoo animals or that they're hiding among us.

Here are the top 10 alien conspiracy theories that'll have you enraged, confused or genuinely intrigued.