In Back to the Future when Marty first goes to the mall to meet up with Doc he walks past the mall sign which reads Twin Pines Mall. At the end of the movie when he returns to the mall to save Doc and watches Marty-2 go back in time the sign reads Lone Pine Mall, referencing back to when Marty drove over the pine tree in 1955.

So the question is, as in the title, when Marty-2 arrived at the mall would the sign already read Lone Pine Mall, or was it still Twin Pines Mall for him? If it already read Lone Pine Mall would Marty-2 likely return to a new present containing a No Pines Mall?

Mall Signs

  • 16
    The simplest answer is that it always said "Lone Pine Mall", but it didn't always say it until after Marty went back in time.
    – Valorum
    Commented Mar 10, 2016 at 21:56
  • 5
    Obligatory Timey-Wimey Explanation. [][]
    – eidylon
    Commented Mar 10, 2016 at 22:22
  • @Richard That's an answer. You should post it as one. (Really, Back to the Future's model of time travel is inconsistent, but it's pretty clear that there's only ever one timeline, even when that doesn't make much sense. All the tension falls apart, otherwise.)
    – user867
    Commented Mar 11, 2016 at 3:11
  • 1
    There is only one timeline, and how things change is governed by the "ripple effect". It appears in the movies that things which lead to paradoxes (if Marty prevents himself from being born, he can't prevent himself from being born) the ripple effect is much slower. For other things it's near-instantaneous). The name of the mall is a trivial detail, so it changed right away. Commented Mar 14, 2016 at 14:06
  • 1
    @Richard, because anything else would be confusing to the audience. If the mall sign had changed without us seeing Marty run over one of the pine trees, we would probably be discussing the apparent continuity error. Commented Mar 14, 2016 at 16:23

4 Answers 4


Marty#1 comes from Universe#1

When he's going back in time, and when he has crushed the pines, he has create a new Universe : Universe#2

So, at the end of the first movie, when he's going back to the future, that's the future of the Universe#2, in which the Lonely Pine is the good name for the mall.

When Marty#2 is arrived at the mall, the sign is already named "Lone Pine Mall"
When Marty#1 is arrived at the mall, the sign is already named "Lone Pine Mall"

  • And when Marty #2 went back in time, there could still have been two pines, which got changed to one pine after Marty-2's involvement in 1955.
    – TOOGAM
    Commented Mar 15, 2016 at 3:06

Within the Back to the Future-verse, timelines don't change until the action that caused the change actually occurs in realtime, as the camera follows the actor. We see this most clearly when Marty saves his parents and their kiss revives him and when he prevents Mad-Dog Tannen from killing the Doc and the gravestone changes.

That being the case, the Twin/Lone Pines Mall sign wouldn't have changed until Marty actually hit the pine in the past, despite this being a logical paradox (it already happened in the past, which means that it should already have occurred). This would mean that Marty-1 should also have run past a sign that read 'Lone Pines Mall' since the accident that damaged the tree occurred in the past, albeit that past event was his in personal future.

Quite how this can be explained in-universe is anyone's guess. I find it best not to think too hard about it.

  • Did you mean Marty-2?
    – Xantec
    Commented Mar 14, 2016 at 13:34
  • @Xantec - I meant Marty-1. The sign only changes once he's gone back in time, but why? Surely the events are in the past, not the present. It's not logical that the sign should change simply because the camera isn't currently following the version of him that's currently in the past.
    – Valorum
    Commented Mar 14, 2016 at 13:49
  • I don't think there's any solid evidence that anyone (other than the audience, who exist outside the timeline) actually remembers there ever having been a "Twin Pines Mall" at the end of the film. Of course, there's also no entirely convincing reason to assume that they don't, given that the films do seem to contain plenty of instances of characters in fact remembering things that, in the changed timeline, never happened. Commented Mar 15, 2016 at 17:56
  • It’s no contradiction if the mall was always called “Lone Pine” as even then, there’s a past where two pines existed on a farm but just one remained when the mall was built (and we know what happens in-between). So the name “Two Pines” for the mall only exists in Marty’s memory and since he’s the only one, people would just say he’s wrong, maybe he’s mixing it up with the name of the farm that was once there. Except the audience because the camera show exactly his point of view, be it right, wrong or alternate timeline…
    – Holger
    Commented Mar 16, 2016 at 10:48

In the original universe, the name of the mall was Twin Pines Mall. As a side effect of Marty traveling back in time, one of the pines was killed. This affected the space-time continuum, and created a ripple in time which changed future events.

From Marty's point of view, he is travelling outside of that version of the timeline, so in his mind, the name of the mall should be Twin Pines Mall. The Marty he runs into at the end of BTTF is actually in an alternate reality. To Marty 2, the mall has always been called the Lone Pine Mall, and he possesses no memories of the alternate version of reality. This aspect of time travel is known as a causal loop. Marty's past actions are affecting alternate versions of himself.

In the next iteration of the loop, Marty 2 would actually still drive over one of the pines with the DeLorean, and leave one still standing. Because the original Marty ran over the tree, all future versions of him will also do the same thing. This is called a predestination paradox. Basically, Marty's actions when he first traveled back in time will repeat forever unless an outside action is taken upon on it such as time travel which directly affects Marty.

  • 2
    Whilst this is a lovely and neat description of what should happen, the reality is that the film's depiction of time travel is far far messier.
    – Valorum
    Commented Mar 15, 2016 at 15:08

When Marty first jumped back in time, his car appeared on Peabody Farm - right where Twin Pines Mall was built. There were two pines in front of the Peabody farm house back in 1955, which grew to become two large pine trees side-by-side two decades later. Marty hit one of the pine trees as he drove away to escape Mr. Peabody and his shotgun.

The moment occurs at 1:56 in this movie clip.

Naturally, with one pine gone in the new timeline, the mall is named Lone Pine Mall.

Not the answer you're looking for? Browse other questions tagged or ask your own question.