When I was a preschooler we drove across country.  We stopped to see a great-grandmother in Idaho and I remember as we left there were rolling hills of green, and nothing else, forever. 

I have often dreamed of those hills and as an adult passing through, I couldn't find them. It's made me feel as if I imagined them.  Turns out, that earlier memory did not occur on the interstate which is now the way to go, and has been for the last 40 years. 

And, thus, another mystery is solved....