The idea that Earth has been visited by aliens at some point in the distant past is not a new one. Erik Von Daniken first touted the theory in his book, The Chariots of the Gods, back in the 1970's. Many people's first introduction to this concept has been via Von Daniken's ideas. While he was widely read, the problem always was that his interpretation of ancient texts and artifacts has always lacked a certain key. Zecharia Sitchin provided that key!