"I can assure you that flying saucers, given that they exist, are not constructed by any power on Earth."

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If they are not an advanced race from the future, are we dealing instead with a parallel universe, another dimension where there are other human races living, and where we may go at our expense, never to return to the present? From that mysterious universe, are higher beings projecting objects that can materialize and dematerialize at will? Are UFOS "windows" rather than "objects"?

— Jacques Vallee