If we look thoroughly at the history of U.F.O sitings and the multitude of eyewitness accounts of alien visitation you will see that there is most definitely a regular pattern, not to mention 100 years ago we were using horse and carriage and now all of the sudden we are technologically advanced.
One of the theories out there says we were just as intelligent 500 years ago as we are today, if we were then wouldn't we have had electricity and computers 500 years ago? Technology changed very little over the centuries until the 19th & 20th century, its as if all of the sudden out of nowhere we became intelligent enough to invent computers and all the things of the modern era.
The truly ironic thing is with spacecraft, computer, satellite and electronics technology that just seems to have burst-ed into life around the mid 20th century, right around the time of Roswell and sitings all over the world, it is my guess that it is most likely not our technology and actually belongs to extraterrestrials visiting our planet.
It is obvious that with some of the knowledge we possess such as nuclear technology we are idiots, I say this because if natural disasters do not destroy the human race, we will destroy ourselves as we are just as power hungry today as we were 1000 years ago.