Jack of Harts

The Fermi Paradox asked why, if life was common, we had no Contact with aliens.  As we expanded, we began to worry that the answer was that they were simply too far away.  We could only travel a hundred lightyears away before hitting The Wall.  On a galactic scale, we were walking around the block, and could not see across the street.    There could have been someone on the other side of the street, let alone the other side of the city, and we never would have known.