I've seen many UFO sighting videos on YouTube and a whole bunch of documentaries on aliens visiting planet Earth for thousands, if not, millions of years with their highly advanced space crafts and technology.
There have even been pictures drawn by ancient egyptions on walls showing beings that do not look human, visiting this planet.
There is also the pyramids of egypt. Many people believe that humans could have never been able to make such structures and that some kind of more advan