Okay, Back to the Future is one of my favorite movies of all time, I grew up on that film, I've watched it countless times over the years, and I have never noticed something that was just pointed out to me today by one of our readers.
Did you ever notice what the effect of time travel had on the Twin Pines mall? When Marty first goes to meet Doc Brown at Twin Pines Mall we clearly see that it's called... "Twin Pines Mall". After Marty comes back from his adventures in 1955 to see Doc Brown get shot up, the sign reads "Lone Pine Mall."
Why did it go from twin to lone? The land that the mall is on was owned by Old Man Peabody, remember that? Now remember when Marty time traveled back in time and crashed into their barn? Well, when Marty drves away with Peabody firing a shot gun at him he runs over one of a pair of pine trees in Peabody’s front yard. Here is a great little visual aid I was pointed out to on reddit that explains it all.
After all of these years of watching this movie, I can't believe I never noticed this!