Platapus, in my opinion one of the best signs that there are extraterrestrials lies in ancient rock art. Dismissed by skeptics as fanciful legends, there are almost identical images portrayed around the world.
pardon the stereotypes to follow, but these are what were drawn millenia ago.
- long, cigar-shaped images painted high above images of ground-dwelling creatures
- images of humanoids with bowls around their heads and clothed in an entirely different fashion to other images in the same area, from the same period.
Another
possible indicator is pyramids. Don't dismiss me yet. Pyramids were constructed in Egypt (arguably the most advanced civilisation at that time, as well as being very close to the so-called 'cradle of civilisation'), as well as being built in S-E Asia and South America.
Again, skeptics can dismiss these, using the argument that a pyramid is the most stable of (relatively) ancient architectural possibilities. The argument is valid and accurate, but I feel fails to take into account 2 points. Firstly, that not all cultures known to have built pyramids are known to have had an advanced enough system of mathematics to determine that pyramids were the most stable type of building. Secondly, As is the case with the recurring images, the implication from those arguing on this basis is that humans around the globe developed with the same ideas and the same legends, at different points in history and with no (known) method of contact with each other. That is, to me, just as far-fetched as little green men visiting our planet.
Happy as always to discuss
Edit -
here is a link to some decent images. look at a few similarities.