I was watching that show Ape to Man on the History channel and it made me think of an interesting theory. Supposedlly our ancestors killed off all of the Neanderthals, but what if they survived. If several managed to hide underground, they would have evolved to look somewhat like aliens. This would explain them being 7ft tall. Living underground for thousands of years would also cause there skin to turn white and there eyes to get big. Humans living on earth would experience a de-evolution during the ice-age, and this would allow for Neanderthals to evolve faster. I have read on many forums here that there are supposedlly many underground tunnels that have not yet been discovered. If they are thousands of years more advanced than us it would not be hard to go undetected. They could have there headquarters in the middle of Russia or Antartica, and we would not even know.