A seven-year-old boy at an amusement park went into what he thought was a walk through haunted house.  Instead of ghosts, goblins, and coffins, the house consisted of bizarre optical illusions and tricks.  He walked over a bridge that appeared to be leaning but wasn't, navigated a mirror and clear glass maze, and found himself at a dead end in a dark tunnel.  He could not move forward, and a wall to the right blocked his way.  The only other choice was to go left, but the lighting made the left appear pitch black, creating the impression of another wall.  He pushed hard against the front.  It was solid.  The wall to the right was just as strong.

What else was there?

He turned towards the darkness to his left and slowly extended his hand.  He found that he could keep extending.  The pitch black space was the opening.