I believe aliens are real and that they exist because many of our earlier civilizations could not have built those great buildings or structures without the help of some sort of extraterrestrial life form. Like how did they build or get the idea for the pyramids, the Stonehenge, and many other iconic landmarks. Where did the Aztecs go did they all move somewhere else on earth or did they leave the planet?  I even believe that god is an extraterrestrial life form because of how he is show to be floating and in the clouds. Aliens could be in another galaxy or they might even be in another solar system.