This memo is out of this world. Mysterious sightings of ‘three to four-foot tall’ beings decked out in space suits and helmets were reported by witnesses decades ago, newly released Pentagon files reveal.

Add Yahoo as a preferred source to see more of our stories on Google. Adapt or die: How do you grow and evolve to fit into an alien environment? How do you create change in the face of overwhelming power? And how do you tell your extraterrestrial overlords ...