THEY WERE HERE!!!!!!! The marshians came into contact with our first civilizations because their planet was no longer livable. They mated with earth women in certain cultures which created the first beliefs in celestial beings which would become known as gods in Egypt, Mesopotamia, Babylon, and eventually Greece and Rome. Most of such societies had myths of gods mating with earth women to create divine beings like Gilgamesh, Helen of Troy, and Hercules. While these stories maybe highly symbolic they still reflect a basic belief. Do you really think that cavemen suddenly had the capacity to build pyramids and tools. No, they were taught by the aliens which were eventually remembered as gods. There are myths that speak of how the gods were able to BREATHE ON EARTH suggesting that they wore space gear when coming from outer space. Ever seen ancient art? There are images of beings that look like a combination of odd creatures wearing what appears to be modern day space gear. Look this stuff up it's in my books. Furthermore ask yourselves why we are SO DIFFERENT from any other species on earth. We walk upright, have opposable thumbs, and can think logically. The missing link in evolution has been found. We are actually descendants from marshans. This doesn't take away religion either. In fact if you look at creation stories from this point of view you'll realize that the gods or God who created us lived outside of our planet and there wasn't an evolutionary process.
Interestingly enough, this post makes legitimate sense in context.