In every ancient culture, there are drawings of beings coming to earth from the sky. There is a lot of research on this and some believe that it is the aliens that actually came down from the sky. This theory explains a lot of mysteries like the technology behind the pyramids.

In documentary called "ancient aliens" there are some who believe that the missing link between primates and humans was the introduction of alien genetics. The aliens are supposed to have genetically altered the primate into humans.

If what was believed to be god was actually aliens then we have another question. Who created this aliens :)