Throughout its history, Earth has been the stage of many acts in the play of Humanoid galactic history. Many extraterrestrial civilizations have walked the face of the Earth, both humanoid and non-humanoid races, and they have done so, long before man even existed. Together with mankind, they have written the history of this Planet. Therefore, it is important to realize that you cannot really understand the history of mankind, nor the history of Earth, until you are aware of the part that was played by these extraterrestrial civilizations. This means, e.g., that you cannot understand the history of mankind if you do not know that Homo Sapiens was not the product of a natural evolution, but was in fact the result of a cross breed of genes of terran primates, and humanoid aliens. (We are not saying Darwin was wrong, or that there is no such thing as evolution. We're only saying that Homo Sapiens appeared too soon, and with too many distinguishing features to be the result of a natural evolution. Did you ever wonder why scientists do not succeed in finding the least trace of "the missing link" between Homo Sapiens and Neanderthal? Now, you know why).Source