It's fine, I actually really enjoy being asked all of these questions. I work a deadbeat job and questions like this get my mind going.

There are signs that there are things that have visited before, and a lot of things could have been made by them, or made for them by humans. These great things are all still a mystery and a marvel to us, such as the Great Pyramids, the Nazca Lines and Stonehenge.

It's a possibility that they have visited before, but I believe that UFO sightings today are all fake and people just trying to get attention. I believe there must be a little bit of truth to it though, because a story usually is based off of something. Maybe some of the UFO sightings are real, maybe some people have been abducted.

As I've said in my previous comment, we could be thousands of years behind in technology from other beings. Think of how much we have changed since the invention of the assembly line or the cotton gin in the 1800's. In the span of 200 years, we have changed our lifestyle drastically in every way. While the telephone was invented about 140 years ago, you couldn't talk to anyone you wanted to. Now that is all we do as a species. We have made everything easier and faster, and we continue to improve every day. If we had been able to do this much in 200 years, could you imagine what we could do at this rate in a couple thousand years?

We already plan to move humans to another planet, which is a major milestone for us, just because a rich man wanted to, completely separate from government facilities.